Newton’s Laws of Motion and
Free Body Analysis
1. M1= 2.5kg and M2=3.5kg
An external force F= 12 Newtons is applied to m1. Calculate (a) the
acceleration of the system, and (b) the tension force between m1 and m2.
a)2.0m/s/s b) 7.0 N
2. A Block of mass 0.50 kg travels with a speed of 2.0 m/s in the positive x direction on a flat
frictionless surface. On passing through the origin, the block experiences a constant force of 3.0
newtons, at a 60 deg angle relative to the x axis for 1.50 seconds. Calculate the velocity of the block at
the end of this time.
V=(6.5m/s)i+(7.8m/s)j
3. If m1=5.0kg, m2=1.5 kg, and theta is 20 degrees, what is the acceleration of
the system. Make your own free body diagram for M2 and assume no friction.
0.32 m/s/s
Static and Kinetic Friction
Table 4.1
Approximate Values for Coefficients of Static and Kinetic
Friction between Certain Surfaces
4. If the coefficient of static friction is between the 40 kg crate and the floor is 0.065. What
is the magnitude of the horizontal applied force the worker must apply to keep the crate
moving? If the worker maintains that force once the crate moves and the coefficient of
kinetic friction is 0.500, what is the magnitude of the acceleration of the crate?
1.48 m/s/s
A crate sits in the middle of a flat bed truck that is traveling at 80 km/hr on a
level road. The coefficient of static friction between the crate and the truck is
0.40. What is the minimum stopping distance for the truck if the crate is not to
slide?
62m
5. If the coefficient of friction is 0.560, what should be the value of m3 if
the system is not to accelerate? Given m1=0.150kg, m2=0.250 kg.
if m3=0.100 kg, what is the acceleration of the system?
0.179 kg, 0.862 m/s/s
6. The Atwood’s machine
was invented by British scientist
George Atwood to study motion . If
m1=0.55 kg and M2=0.80 kg, calculate
the acceleration of the system, and the
tension in the string.
1.8m/s/s, 6.4 N
7. In the frictionless system shown below (m1=2.0 kg), what is
mass m2, if the system is to remain at rest?
1.2 kg
8. The two blocks remain stuck together as they are pulled to the right by a
force F=200N. The coefficient of kinetic friction between block b and the table
top is 0.800. a) Calculate the acceleration of the system b) calculate the force
of friction between the two blocks.
A) 5.5 m/s/s b) 173 N