CHAPTER 4

... FTmax = m(a + g) = (1200 kg)(0.0600 + 1)(9.80 m/s2) = 5.04104 N. The minimum tension will be exerted by the motor when the elevator is accelerating downward. We write ∑F = ma from the force diagram for the car: y-component: FTmin – mg = ma, or FTmin = m(a + g) = (1200 kg)(– 0.0600 + 1)(9.80 m/s2 ...

... FTmax = m(a + g) = (1200 kg)(0.0600 + 1)(9.80 m/s2) = 5.04104 N. The minimum tension will be exerted by the motor when the elevator is accelerating downward. We write ∑F = ma from the force diagram for the car: y-component: FTmin – mg = ma, or FTmin = m(a + g) = (1200 kg)(– 0.0600 + 1)(9.80 m/s2 ...

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... 7. Displacement is which of the following types of quantities? a. vector c. magnitude b. scalar d. dimensional ...

... 7. Displacement is which of the following types of quantities? a. vector c. magnitude b. scalar d. dimensional ...

Unbalanced forces acting on an object cause the object to

... Recall that mass (a quantity of matter) and weight (the force due to gravity) are proportional. • A 10-kg cannonball experiences 10 times as much gravitational force (weight) as a 1-kg stone. • Newton’s second law tells us to consider the mass as ...

... Recall that mass (a quantity of matter) and weight (the force due to gravity) are proportional. • A 10-kg cannonball experiences 10 times as much gravitational force (weight) as a 1-kg stone. • Newton’s second law tells us to consider the mass as ...

laws of motion - WordPress.com

... A 200-N wagon is to be pulled up a 308 incline at constant speed. How large a force parallel to the incline is needed if friction eects are negligible? The situation is shown in Fig. 3-10(a). Because the wagon moves at a constant speed along a straight line, its velocity vector is constant. Therefo ...

... A 200-N wagon is to be pulled up a 308 incline at constant speed. How large a force parallel to the incline is needed if friction eects are negligible? The situation is shown in Fig. 3-10(a). Because the wagon moves at a constant speed along a straight line, its velocity vector is constant. Therefo ...

Working with moving pulleys

... string passing over the pulley. The arrangement is alike static pulley system except that the pulley (B or "C") is also moving along with other constituents of the component systems like string and blocks. If we could treat the moving pulley system static, then the analysis for the motion of block ...

... string passing over the pulley. The arrangement is alike static pulley system except that the pulley (B or "C") is also moving along with other constituents of the component systems like string and blocks. If we could treat the moving pulley system static, then the analysis for the motion of block ...

AP Physics 1 Investigation 2: Newton`s Second Law

... Some of the common challenges that students have regarding Newton’s first law include the idea that forces are required for motion with constant velocity. When observing the demonstrations, students need to recognize that the velocity of the object is changing as a result of the net force exerted on ...

... Some of the common challenges that students have regarding Newton’s first law include the idea that forces are required for motion with constant velocity. When observing the demonstrations, students need to recognize that the velocity of the object is changing as a result of the net force exerted on ...

Q1 CP Physics Answer Section

... 6. On a position versus time graph, the slope of the straight line joining two points on the plotted curve that are separated in time by the interval t, is which of the following quantities? a. average steepness b. average velocity c. instantaneous velocity d. average acceleration ...

... 6. On a position versus time graph, the slope of the straight line joining two points on the plotted curve that are separated in time by the interval t, is which of the following quantities? a. average steepness b. average velocity c. instantaneous velocity d. average acceleration ...

posted

... F T k mB g Use the first equation to replace T in the second: F k mA g k mB g. (a) F k (mA mB ) g (b) T k mA g EVALUATE: We can also consider both crates together as a single object of mass (mA mB ). Fx max for this combined object gives F f k k (mA mB ) g , in agreeme ...

... F T k mB g Use the first equation to replace T in the second: F k mA g k mB g. (a) F k (mA mB ) g (b) T k mA g EVALUATE: We can also consider both crates together as a single object of mass (mA mB ). Fx max for this combined object gives F f k k (mA mB ) g , in agreeme ...

Student`s Alternative Conceptions of Free

... teacher explained which answer was correct and why. The concepts of free-falling motion free-fall, speed, velocity and acceleration are often introduced to students as parts of natural science courses in university level Physics classes. Physics classes traditionally begin with classical mechanics, ...

... teacher explained which answer was correct and why. The concepts of free-falling motion free-fall, speed, velocity and acceleration are often introduced to students as parts of natural science courses in university level Physics classes. Physics classes traditionally begin with classical mechanics, ...

Student Text, pp. 88-96

... Directions in Pulley Problems When you solve a problem that involves at least one pulley, choose a general positive direction for the entire system of objects. You should then assign a +x or +y direction for each object so that it is in the general positive direction. For example, the system of obje ...

... Directions in Pulley Problems When you solve a problem that involves at least one pulley, choose a general positive direction for the entire system of objects. You should then assign a +x or +y direction for each object so that it is in the general positive direction. For example, the system of obje ...

Force, Mass, and Acceleration

... person holding it in position. You will need to zero the force sensor, before each run. To do that you need to push and hold the zero button on the sensor for a few seconds but you will need to do that with no force acting on the sensor. So you will have to make the string go slack before you zero t ...

... person holding it in position. You will need to zero the force sensor, before each run. To do that you need to push and hold the zero button on the sensor for a few seconds but you will need to do that with no force acting on the sensor. So you will have to make the string go slack before you zero t ...

Chapter 3 - Welch Science Home

... 6. A race car’s velocity increases from 4.0 m/s to 36 m/s over a 4.0-s time interval. What is its average acceleration? 7. The race car in the previous problem slows from 36 m/s to 15 m/s over a 3.0 s. What is its average acceleration? 8. A car is coasting backwards downhill at a speed of 3.0 m/s wh ...

... 6. A race car’s velocity increases from 4.0 m/s to 36 m/s over a 4.0-s time interval. What is its average acceleration? 7. The race car in the previous problem slows from 36 m/s to 15 m/s over a 3.0 s. What is its average acceleration? 8. A car is coasting backwards downhill at a speed of 3.0 m/s wh ...

OCR GCSE Science Physics A and B PAG 3: Motion

... 2. Release (do not push) the trolley from the top of the ramp, start the timer and record the time taken for the trolley to move the whole distance of the ramp. 3. Repeat this 2 more times and calculate the mean. Record results in the table below. 4. Release (do not push) the trolley from the top of ...

... 2. Release (do not push) the trolley from the top of the ramp, start the timer and record the time taken for the trolley to move the whole distance of the ramp. 3. Repeat this 2 more times and calculate the mean. Record results in the table below. 4. Release (do not push) the trolley from the top of ...

# Proper acceleration

In relativity theory, proper acceleration is the physical acceleration (i.e., measurable acceleration as by an accelerometer) experienced by an object. It is thus acceleration relative to a free-fall, or inertial, observer who is momentarily at rest relative to the object being measured. Gravitation therefore does not cause proper acceleration, since gravity acts upon the inertial observer that any proper acceleration must depart from (accelerate from). A corollary is that all inertial observers always have a proper acceleration of zero.Proper acceleration contrasts with coordinate acceleration, which is dependent on choice of coordinate systems and thus upon choice of observers.In the standard inertial coordinates of special relativity, for unidirectional motion, proper acceleration is the rate of change of proper velocity with respect to coordinate time.In an inertial frame in which the object is momentarily at rest, the proper acceleration 3-vector, combined with a zero time-component, yields the object's four-acceleration, which makes proper-acceleration's magnitude Lorentz-invariant. Thus the concept is useful: (i) with accelerated coordinate systems, (ii) at relativistic speeds, and (iii) in curved spacetime.In an accelerating rocket after launch, or even in a rocket standing at the gantry, the proper acceleration is the acceleration felt by the occupants, and which is described as g-force (which is not a force but rather an acceleration; see that article for more discussion of proper acceleration) delivered by the vehicle only. The ""acceleration of gravity"" (""force of gravity"") never contributes to proper acceleration in any circumstances, and thus the proper acceleration felt by observers standing on the ground is due to the mechanical force from the ground, not due to the ""force"" or ""acceleration"" of gravity. If the ground is removed and the observer allowed to free-fall, the observer will experience coordinate acceleration, but no proper acceleration, and thus no g-force. Generally, objects in such a fall or generally any such ballistic path (also called inertial motion), including objects in orbit, experience no proper acceleration (neglecting small tidal accelerations for inertial paths in gravitational fields). This state is also known as ""zero gravity,"" (""zero-g"") or ""free-fall,"" and it always produces a sensation of weightlessness.Proper acceleration reduces to coordinate acceleration in an inertial coordinate system in flat spacetime (i.e. in the absence of gravity), provided the magnitude of the object's proper-velocity (momentum per unit mass) is much less than the speed of light c. Only in such situations is coordinate acceleration entirely felt as a ""g-force"" (i.e., a proper acceleration, also defined as one that produces measurable weight).In situations in which gravitation is absent but the chosen coordinate system is not inertial, but is accelerated with the observer (such as the accelerated reference frame of an accelerating rocket, or a frame fixed upon objects in a centrifuge), then g-forces and corresponding proper accelerations felt by observers in these coordinate systems are caused by the mechanical forces which resist their weight in such systems. This weight, in turn, is produced by fictitious forces or ""inertial forces"" which appear in all such accelerated coordinate systems, in a manner somewhat like the weight produced by the ""force of gravity"" in systems where objects are fixed in space with regard to the gravitating body (as on the surface of the Earth).The total (mechanical) force which is calculated to induce the proper acceleration on a mass at rest in a coordinate system that has a proper acceleration, via Newton's law F = m a, is called the proper force. As seen above, the proper force is equal to the opposing reaction force that is measured as an object's ""operational weight"" (i.e., its weight as measured by a device like a spring scale, in vacuum, in the object's coordinate system). Thus, the proper force on an object is always equal and opposite to its measured weight.