Motion & Newton’s 3rd Law Practice Problems Name:
Physics Period
1. A hockey player prepares to pass the puck. She flings the puck towards her teammate on the frictionless ice.
(a)Which experiences the greater force, the puck or (c) Draw a free body diagram for each, the player
the hockey player? Explain. and the puck.
(b)Which experiences the greater acceleration?
Why?
2. A 71 kg astronaut is in space, working on the exterior of her 2000 kg shuttle, when she accidentally drifts
away from it. Luckily, she is attached by a 10 m long cord. The cord brings her to a stop 10 meters from the
shuttle. She then pulls with a force of 100 N until she is reunited with her shuttle.
(a) Draw the free body diagram on the space shuttle (d) Draw the free body diagram for the astronaut as
while the astronaut pulls on the cord. she pulls on the cord.
(b) What is the force that the astronaut exerts on (e) What is the force that the shuttle exerts on the
the shuttle? astronaut?
(c) What is the shuttle’s acceleration? (f) What is the astronaut’s acceleration?
CHALLENGE: how far does the astronaut go before colliding with her shuttle?
4. Angel, the 12 kg pit bull, is sitting on a 0.5 kg mat in the middle of the kitchen floor. Angel catches sight of
a rabbit in the backyard and suddenly leaps off the mat to the side, pushing it to the left with a force of 35 N for
half a second. The coefficient of friction between the mat and the tile floor is 0.11.
(a) Draw a free body diagram for the mat while (e) Draw a free body diagram for Angel.
Angel leaps.
(b) What is the net force on the mat? (f) What is the net force on Angel?
(c) What is the mat’s acceleration? (g) What is Angel’s acceleration?
(d) How fast is the mat moving after Angel’s push? (h) How fast is Angel moving when she leaves the
mat?
4. Katie, a 60 kg person, stands at the edge of a well and holds a rope attached to an 8 kg bucket of water
resting in the water below. With her first tug up on the rope, the bucket speeds up to 3 m/s while it rises 0.9 m.
a) Draw a free body diagram for the bucket. d) Draw a free body diagram for Katie.
b) What is the bucket’s acceleration? e) How quickly is Katie accelerating?
c) How hard is Katie pulling on the bucket? f) What is the normal force acting on Katie?
5. While on safari, 70 kg Nick sees a 3000 kg white rhino grazing and walks over to take a look. The
rhinoceros gets upset and charges at Nick, so Nick screams and runs. Nick runs to the right at 8 m/s while the
rhino chases after him at 15 m/s. The rhino catches up to Nick and pushes him in the back. After the 0.7
second collision, Nick is sliding across the ground at 25 m/s. The coefficient of friction between Nick and the
ground is 0.7.
a) Draw a free body diagram for Nick as the rhino e) Draw a free body diagram for the rhinoceros
hits him during the collision? [Hint: friction is negligible
for any animal that is running full speed.]
b) How quickly is Nick accelerating during the f) What is the net force on the rhinoceros during
collision? the collision?
c) What is the net force acting on Nick during the g) How quickly does the rhinoceros accelerate
collision? during the collision?
d) How much force does the rhinoceros exert on h) How fast is the rhinoceros moving after the
Nick during the collision collision?