Download Math Practice Problems 2nd 8 weeks

Math Practice – ISCI 2002
Directions: The following questions are to be completed and included in your portfolio. Be sure to
following the criteria described below to get full credit for your practice problems:
(1). Include the problem statement.
(2). Show the basic formula used to solve the problem.
(3). Show all work needed to solve the problem.
(4). Be sure to include units with your answers.
Speed, velocity and acceleration
1.
Calculate the speed of an object that moves 8 meters in 20 seconds.
2.
An object has an initial velocity of 4 m/s. After a period of 20 seconds the velocity of the object increases to 12
m/s. Calculate the acceleration of the object.
3. Determine the acceleration of a car that moves from rest to 15.0 m/s in 10.0 seconds.
4. Determine the average speed of a truck that makes a 285-mile trip in 5.0 hours?
5. An object moves 3.5 cm west from a point of zero origin. It then moves 2.8 cm north. (a) Draw the corresponding
vectors and the vector resultant (b) Determine the displacement of the object from its origin.
6. An airplane moves with a velocity of 22.0 m/s in the (x –direction) and 11.7 m/s in the (y-direction). (a) Draw the
resultant (b). Determine the resultant velocity of the plane.
Force, Motion and Newton’s Laws
1.
There are two opposing forces on a box. A person applies a 50 N force on a box attempting to push it to the right.
The frictional force opposing the box (floor) is approximately 35 N. Draw a vector diagram showing the forces
and direction of the forces. What is the summation of the forces?
2.
A horizontal force of 100-N is required to push a box across the floor at a constant velocity. Draw this situation.
If the box is moving at a constant velocity, the net force equals zero. Explain.
3. Refer to the diagram in your text on page 34 to answer this question. A scaffold in mechanical equilibrium contains
ropes each with a supporting tension of 200N. A person in the middle weighs 250 N. Determine the weight of the
scaffold.
4. Determine the acceleration of an object when you push with a horizontal force of 40-N on a 4-kg mass. There is also
a horizontal frictional force of 2-N.
5. How many Newton’s are there in a 3.5 kg mass?
6. A 747 Jumbo Jet of 30,000 kg experiences a 30,000 N thrust for each of its 4 engines during takeoff. Determine the
acceleration of this jet.
7. You are standing on a skateboard and push with a 30-N force on the wall.
(a). How hard does the wall push back?
(b). Which of Newton’s Laws does this refer to?
(c). If you have a mass of 60-kg and you push on the wall with a 30-N force, what will be your acceleration?
8. An object falls straight down from a cliff and takes 3.0 seconds to hit the ground.
(a) After 2 seconds, what was its speed or velocity in m/s?
(b) How far did it fall during this time?
Momentum Work and Energy
1. A 14-kg object is travelling at a speed or velocity of 10.0 m/s. Determine it’s momentum.
2. What is the velocity of an object that has a momentum of 80.0 kg x m/s if it has a mass of 25-kg.
3. A person pushes an object with a 50-N force for a total distance of 25-m. What work was done on this object?
4. A 2000-N load was lifted a vertical distance of 6.5-m in 3.2 seconds. How much power was expended when lifting
this load?
5. A 125-kg object is moving at a speed of 10.0 m/s. How much kinetic energy does this object possess?
6. A car with a mass of 1000-kg moves at 20.0 m/s. How much braking force is needed to bring the car to a halt in 10.0
seconds?
7. A 1.8 kg cart that is travelling at 4.0 m/s collides with a stationary cart that has a mass of 1.5 kg, lock up and begin
to move as one. Determine the velocity of the ‘coupled’ carts.
Gravity
1. Calculate the force of gravity between the EARTH (6.24 x 10 24) and the Sun (2.0 x 1030 kg). The average distance
between the two is 1.5 x 1011 meters.
Electricity
1. A devise in a 120-V circuit has a current rating of 20.0-A. Determine the resistance of this devise.
2. What is the current drawn by a 1200-W hair dryer connected to a 120-V (10-A) system?
3. At 10,000 OHMs, how much current will flow through your body if you touch the terminals of a 12-V battery?
Sound and Light
1. Calculate the frequency, in hertz, that corresponds to each of the following periods:
(a) 0.10 seconds
(b) 5.0 seconds
2. If a train of freight cars, each 15-m long, rolls by you at the rate of five cars per second, what is the speed of the
train?
3. A sound wave with a frequency of 260 Hz has a wavelength of 1.27 m. With what speed would you expect this
sound wave to move?
4. Water waves are observed to pass under a bridge at a rate of one complete wave every 4.0 s. Determine the period
and frequency of these waves.
5. During a thunderstorm, thunder was timed 4.63 seconds after lightning was seen. How many feet away was the
lightning strike if the speed of sound is 1,140 ft/s?