Honors Physics
Circular Motion (with Gravitation) Review Problems
1.
Aircraft experience a lift force that is perpendicular to the plane of the wings and to the direction of
flight. A small aircraft is flying at a constant speed of 240 km/h. At what banking angle from the
horizontal must the wings of the aircraft be tilted for the aircraft to execute a horizontal turn with a
radius of 1200m?
2.
A bowling ball weighing 71.2 N is attached to the ceiling by a 3.8 m rope. You pull it to one side and
release it. It swings back and forth. As the rope swings through the vertical, the speed of the bowling
ball is 4.2 m/s.
a. What is the acceleration of the bowling ball in magnitude and direction at this instant?
b. What is the tension in the rope?
c. If the ball were not moving, what would be the tension in the rope? Surprised?
3.
A crate of eggs is located in the middle of the flatbed of a pickup truck as the truck negotiates an
unbanked curve in the road. The curve may be regarded as an arc of a circle of radius 39.0 m. If the
coefficient of static friction between the truck and the crate is 0.625, how fast can the truck be moving
without the crate sliding?
4.
A 600 kg satellite is in a circular orbit about the Earth at a height above the Earth equal to the Earth’s
mean radius.
a. What is the satellite’s orbital speed?
b. What is the period of its revolution?
c. What is the gravitational force acting on it?
5.
There is a point along the line joining the center of the earth to the center of the moon at which the two
gravitational forces cancel. Find this point’s distance, x, from the earth’s center. Use D for the earthmoon distance, and me and mm for the masses of earth and moon respectively.
6.
A pail of water is rotated in a vertical circle of radius equal to 1.25 m.
a. What is the minimum speed of the pail at the top of the circle if no water is to spill out? An
FBD helps!
b. The pail is rotated at a constant rate so it has the minimum speed at all points along its circular
path. The mass of the water is m. When the pail is at the bottom of the circle, what is the
magnitude of the force exerted by the water on the bottom of the pail?
c. What is the magnitude of the force exerted by the water on the bottom of the pail when the
pail is halfway between the bottom and the top of the circle?
7.
Three 8 kg masses are located at points in the xy plane. One mass is at the origin. A second mass is at
(x,y) of (0,50cm). The third mass is located at (45cm, 0). What is the magnitude of the total force of
gravity felt by the mass at the origin? At what angle from the positive x-axis will the resultant force
point?
Momentum Review Answers:
1a) 350 1b) 1167; 2) 0.14; 3) 6.3, 126; 4) 19.8, 40.9; 5) 196, 22.7 6) 41.58; 7) 163
Honors Physics – Momentum Practice Problems
1.
Imagine that you are parked at a stop light. Suddenly your car is accelerated to a speed of 5 m/s by a
rear end collision. Your mass (in case you forgot) is 70 kg. Assume that the time of the collision is
0.3 s. a) Find the impulse on you and b) find the average force exerted on you by the back of the seat
of the car.
2.
A 16g mass is moving in the +x direction a 30 cm/s while a 4 g mass is moving in the –x direction at
50 cm/s. They collide head on and stick together. Find their velocity after the collision.
3.
A football of mass 0.42 kg is passed with a velocity of 25 m/s due south. A defending player lunges at
the ball and deflects it so that the new velocity is 20 m/s, 36.9 0 west of south. Find the magnitude of
the impulse. If the player is in contact with the ball for 0.05s, what is the magnitude of the average
force he exerts?
4.
A ghostly white Honda Civic with a mass of 1200 kg is moving east at 30 m/s and collides with a sky
blue Ford pick-up truck with a mass of 3600 kg moving at 20 m/s in a direction 600 north of east. The
vehicles interlock and move off together. Find their common velocity and the angle that describes
their new direction.
5.
Imagine that you are riding a skateboard at 3.2 m/s across a frictionless floor (technically, you are
sliding across the floor). The skateboard has a mass of 10 kg while you weigh 600 N. You jump off
the skateboard and land without injury on the floor at zero velocity. What impulse did you give to the
skateboard? What was the velocity of the skateboard after you jumped off?
6.
Suppose you have two putty balls (of the same mass) both moving along a frictionless floor with a
velocity of 45 m/s. They collide and stick together. Interestingly, their trajectories of travel leading to
the collision have an angle of 45o between them. Find their final velocity.
7.
Suppose that a horizontal force of 0.70 N is required to pull a 5 kg block across at a rough table at a
constant speed. What is the speed of a 20 g bullet, if the bullet embeds in the block and causes the
block to slide 1.5 m before coming to rest?
Answers for Circular Motion Review
1
21o
5
x
2
3
4
4.6, 105, 71.2
15.5
5.58E3, 1.44E4 s, 1.47E3
6
7

D me  (me mm )1/ 2
me  mm
v=3.5, F=2mg, F=mg
2.7139E-8, angle=39o
