Download Review Problems 4.27

1. A jet fighter plane is launched from a catapult on an aircraft carrier. It
reaches a speed of 42 m/s at the end of the catapult, and this requires
2.0s. Assuming the acceleration is constant, what is the length of the
catapult?
2.
A ball is thrown straight up with a speed of 36.0 m/s. How long does
it take to return to its starting point?
3. A ball is thrown with a velocity of 20 m/s at an angle of 20° above the horizontal.
What is the horizontal component of its instantaneous velocity at the exact top of
its trajectory?
4. Two rocks are dropped into two different deep wells. The first one
takes four times as long to hit bottom as the second one. Ignore air
resistance. How much deeper is the first well than the second?
5. A ball is thrown from a roof with a speed of 10.0 m/s and an angle of 37o with
respect to the horizontal. What are the vertical and horizontal components of
the ball’s displacement 2.5 seconds after it is thrown?
6. A 5.0 kg copper block is sliding along a steel surface (µk = .36) as it is pulled
with a force of 50 N. Calculate the force of friction acting on the block as it is
pulled. Calculate the net force on the block and its resulting acceleration.
7. An object is accelerating at 2 m/s2. If the net force is tripled and the mass is
halved, then what is the new acceleration?
8. What force is needed to accelerate a 60.0 kg cart and rider from rest to 4.2
m/s in 2.5 seconds when the friction force is 24 N?
9. What tension would accelerate a 5.0 kg object suspended on a string
a) upwards at 6.2 m/s2?
b) downwards at 6.2 m/s2?
10.
An elevator accelerates upward at 1.5 m/s2. If the elevator has a mass of
200 kg, find the tension in the supporting cable.
11.
The weight of the block on the table is 111 N and the weight of the
hanging block is 258 N. Ignoring all frictional effects and assuming the pulley
to be massless, find the acceleration of the two blocks, and the tension in the
cord.
12.
At the end of a production line, a 50 kg box slides down an inclined ramp.
The coefficient of friction on the ramp is 0.5. The ramp is at a 350 angle to the
horizontal.
a) What is the normal force on the box?
b) What is the acceleration of the box?
c) If the ramp is 10 m long and the box starts from rest, what is the box's
speed at the bottom of the ramp?
13.
A 1200 kg car traveling North at 20 m/s collides with a 1400 kg car
traveling South at 22 m/s. The two cars collide and entangle. What is the
resulting velocity of the wreckage?
14.
A 5 kg cart is moving horizontally at 6 m/s. In order to change its speed
to 10 m/s, the net work done on the cart must be:
15. Two objects having the same mass travel toward each other on a flat surface, each with
a speed of 10 meter per second relative to the surface. The objects collide head-on and
are reported to rebound after the collision, each with a speed of 20 meters per second
relative to the surface. Which of the following assessments of this report is most
accurate?
A)
B)
C)
D)
E)
Momentum was not conserved; therefore, the report is false.
If potential energy was released to the objects during the collision, the report could
be true.
If the objects had different masses, the report could be true.
If the surface was inclined, the report could be true.
If there was no friction between the objects and the surface, the report could be
true.
A railroad car of mass m is moving at speed υ when it collides with a
second railroad car of mass M which is at rest. The two cars lock together
instantaneously and move along the track. What is the speed of the cars
immediately after the collision?
16.
17. An open cart on a level surface is rolling without frictional loss through a
vertical downpour of rain, as shown above. As the cart rolls, an appreciable
amount of rainwater accumulates in the cart. The speed of the cart will
A) increase because of conservation of momentum
B) increase because of conservation of mechanical energy
C) decrease because of conservation of momentum
D) decrease because of conservation of mechanical energy
E) remain the same because the raindrops are falling perpendicular to the
direction of the cart's motion