Download Review Forces Part 2

Forces Review – Part 2, continued
1. For the problem below, determine all the missing numbers (hint: start with Fg). Note: velocity is
constant.
2. A 5 kg box is sliding down a ramp (ramp angle of 50º), determine
a) weight of the box
b) normal force
c) acceleration if µ=0
d) acceleration if µ=0.15
3. A block of mass 15 kg is on an incline at an angle of 30º. If the block does not slide,
a) determine the frictional force exerted on the block.
b) what is the coefficient of friction?
c) If the block was sliding at a constant velocity, what is the frictional force on the block?
d) If the ramp in this problem were frictionless, what would be the acceleration of the block?
4. Two masses are connected by a light cord over a frictionless pulley. If
the coefficient of kinetic friction is 0.18 between the 10 kg block and
the table, what is:
10 kg
a) the acceleration of the system?
b) the tension in the cord?
5. Using the pulley in the figure to the right, (no friction!) Assume m1 = 6 kg and m2
= 2 kg.
a) Calculate the acceleration. (Be sure to indicate direction on your picture!)
b) What is the tension in the string?
6.4
kg
Figure Problem 5
6. A block of mass 10 kg is placed on a smooth incline which makes an angle of 20º with the
horizontal.
a) What is the acceleration of the block?
b) What is the distance covered in 10 s, if the initial velocity is 1.5 m/s?
7. A boy on a sled (total mass = 80 kg) is sliding down a snow-covered hill. The slope is at an angle
of 15 to the horizontal. Find the boy’s
a) acceleration if there is no friction.
b) acceleration if the coefficient of friction is 0.55.
c) Is it possible to be sliding down the hill if your acceleration is up the hill? Why or why not?
8. Using the pulley in the figure to the right, to the right, (the coefficient of
friction between the 8 kg block and the table is 0.15),
Figure Problem 8
8 kg
a) Calculate the acceleration. (Be sure to indicate direction on your
picture!)
12 kg
b) What is the tension in the string?
9. Using the pulley in the figure to the right, (no friction!) Assume m1 = 3 kg and m2 = 7 kg.
a) Calculate the acceleration. (Be sure to indicate direction on your picture!)
b) What is the tension in the string?
Figure Problem 9