CP PHYSICS
FORCES REVIEW
Name: _________________________________
____ period
I.
Equilibrium Forces
1.
A 12 N fish is weighed with 2 spring scales, each of negligible weight.
a. What would the scales read if they were hung end-to-end?
________
b. If they were hung side-by-side, what would each scale read? ________
2.
What are the four basic forces in the universe? Define each.
a. __________________________________________________________________
b. __________________________________________________________________
c. __________________________________________________________________
d. __________________________________________________________________
3.
Which is the strongest force? __________________________
4.
Which is the weakest force? __________________________
5.
Define the following:
a. concurrent forces:
b. resultant force:
c. equilibrant force:
6.
What is the resultant of these forces: 31 N north and 14 N south?
7.
What is the equilibrant force for #6?
8.
Two forces act on an object: 470 N east and 630 N south. Draw a diagram and
determine the resultant force. What is the equilibrant force?
9.
Two movers pull on ropes attached to a large piece of furniture. If one mover
pulls with a force of 250 N west, and the second mover pulls with a force of
335 N north, what is the resultant force acting on the furniture? What equilibrant
force is required to keep the furniture moving at a constant velocity?
CP PHYSICS, FORCES REVIEW, page 2
II.
Friction
1.
The force that enables a car to “make a curve” or that keeps you from sliding on the
sidewalk is __________________.
2.
What are the two types of friction? Define each.
a. __________________________________________________________________
b. __________________________________________________________________
3.
Static friction is (<, =, >) sliding friction for two surfaces in contact.
4.
Compared to an object’s motion, in which direction does friction act? ___________
5.
What does the force of friction depend on?
a. _____________________________________________________
b. _____________________________________________________
c. _____________________________________________________
6.
Does the area of contact affect the force of friction between surfaces? _________
7.
Draw a free body diagram showing constant velocity. Label all the forces acting on
the object and give the action-reaction pairs of forces. Which of Newton’s laws applies?
8.
Draw a free body diagram showing acceleration. Label all the forces acting on the
the object and give the action-reaction pairs of forces. Which of Newton’s laws applies?
9.
A horizontal force of 48 N is required to slide a 2.0 kg box across a tile floor at constant
velocity. What is the coefficient of sliding friction between the box and the floor?
CP PHYSICS, FORCES REVIEW, page 3
10.
A bulldozer drags a log weighing 500 N at uniform velocity. If the applied force is 224 N,
what is the coefficient of friction?
11.
A 425 N laboratory cart with a 28 N box on top of it is pushed down a hallway at constant
velocity. The coefficient of friction between the cart’s wheels and the floor is 0.67. What
force is being applied to the cart?
12.
A 730 N ice skater is pushed across the ice on a skating by a friend. The coefficient of
friction between the skater’s ice skates and the ice is 0.13. What force must the friend
apply to push the skater at a constant speed across the rink?
13.
A 198 kg video cart is rolled down a hallway. It is accelerated at 0.10 m/s2. If a force of
245 N is applied to move the cart, what force of friction do the wheels have against the
floor?
14.
A 24 kg bowling ball is rolled down the bowling alley lane. The ball accelerates at
1.1 m/s2. If the force of sliding friction between the ball and the lane is 94 N, what was
the force applied to the bowling ball?
CP PHYSICS, FORCES REVIEW, page 4
III.
Vertical Motion Forces
1.
Draw the free body diagram for an object launched upward into the air. Label all the
forces acting on the object and explain which of Newton’s laws of motion applies.
2.
A 5.0 kg ball is launched upward with a force of 85 N. What is the ball’s upward
acceleration?
3.
A 1225 N rocket is launched into the air. Its engines exert an upward force of 4250 N.
What is the rocket’s acceleration?
IV.
Inclined Planes
1.
What direction are weight vectors always drawn?
2.
What acceleration will be reached as the angle of incline approaches 90 o?
3.
Draw an inclined plane with an object on it and label all the forces acting on the object.