PHYSICS -CP
Force Problems
Equations: Fnet=ma
Name:____________
(Sheet #3)
Fgrav=mg
use g=9.8 m/s/s on the Earth
SHOW ALL WORK including the equation(s) used to get full credit. This worksheet will
be turned in at the end of class today. You may discuss with each other, but don’t write as
you talk.
(1) Batman (70kg) is accelerating upwards at 3m/s/s by the wire attached to his belt.
a) Find the net force on Batman:
Fnet=
b) Draw a free body diagram and find the tension in the wire:
(2) A 40N tension force is pulling a 6kg crate over a rough surface. As a result
of this force the crate continues to move at a constant speed. Draw FBD (4
forces). What must be the frictional force produced by the rough surface?
(3) A 400 N applied force to the right is found to accelerate a 20
kg bag over a rough floor surface at the rate of 15 m/s2 to the
right. Draw fbd. What must be the force of friction ?
(4) Joe is pushing horizontally with a force of 75 N on a crate sitting at rest on the floor. The crate has
a weight of 450 N. The crate has not begun to accelerate.
a. Draw the FBD for the crate
b.
c.
d.
e.
f.
What is the weight of the crate? ______________ N
What is the normal force acting on the crate? ______________ N
What force is being applied to the crate? __________________ N
What is the net horizontal force acting on the crate? ______________ N
What type of friction is present between the crate and the floor? _____________
What is the force of friction acting against Joe? ________________
(5) A 4kg can of paint is being lowered by a string. If the tension in the
string is 32N, what is the acceleration of the paint can? Draw FBD:
(6) A 50kg person on an elevator which is moving upwards at 8m/s comes to a stop in 2 sec.
a) Find the acceleration of the person
b) Find the net force acting on the person.
c) Find the normal force acting on the person? Draw FBD:
(7) A 28 N force is exerted on an object of unknown mass. The object’s acceleration is
observed to be 4 m/s/s.
a) Draw FBD (2 horizontal forces).
b) Assuming the surface was producing an 8 N frictional force, what mass was being pulled ?
(8) A cable is pulling up a 50kg person starting from rest. If the maximum tension the cable
can handle is 2000N, what is the acceleration of the person? Draw
FBD: