Practice Test | |

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Practice Test

Part 1: MCQ

1. If

a.5.3 m/s2

b.4.4 m/s2

c.3.5 m/s2

d.6.2 m/s2

e.8.4 m/s2

2. The tension in a string from which a 4.0-kg object is suspended in an elevator is equal to 44 N. What is the acceleration of the elevator?

a.11 m/s2 upward

b.1.2 m/s2 upward

c.1.2 m/s2 downward

d.10 m/s2 upward

e.2.4 m/s2 downward

3. A 2.0-kg block slides on a frictionless 25° inclined plane. A force of 4.6 N acting parallel to the incline and up the incline is applied to the block. What is it’s acceleration?

a.1.8 m/s2 up the incline

b.2.3 m/s2 up the incline

c.6.6 m/s2 down the incline

d.1.8 m/s2 down the incline

e.2.3 m/s2 down the incline

4. A 1.5-kg object has a velocity of 5

a.3.8 N

b.3.2 N

c.2.8 N

d.4.3 N

e.4.6 N

5. Only two forces act on a 3.0-kg mass. One of the forces is 9.0 N east, and the other is 8.0 N in the direction of 62° north of west. What is the magnitude of the acceleration of the mass?

a.2.0 m/s2

b.2.4 m/s2

c.3.3 m/s2

d.2.9 m/s2

e.5.7 m/s2

6. The total force needed to drag a box at constant speed across a surface with coefficient of kinetic friction

a. sin

b. cos

c. tan

d. cot

e. sec

7. A 5.0-kg mass sits on the floor of an elevator that has a downward acceleration of 1.0 m/s2. On top of the 5.0-kg mass is an object of unknown mass. The force of the elevator on the 5.0-kg mass is 80 N up. Determine the unknown mass.

a. 3.3 kg

b. 2.4 kg

c. 1.6 kg

d. 4.1 kg

e. 5.0 kg

8. A block is pushed across a horizontal surface by the force shown. If the coefficient of kinetic friction between the block and the surface is 0.30,

a. 2.8 m/s2

b. 2.3 m/s2

c. 1.8 m/s2

d. 3.3 m/s2

e. 5.4 m/s2

9. Two blocks in contact with each other are pushed to the right across a rough horizontal surface by the two forces shown. If the coefficient of kinetic friction between each of the blocks and the surface is 0.30, determine the magnitude of the force exerted on the 2.0-kg block by the 3.0-kg block.

a. 15 N

b. 25 N

c. 11 N

d. 22 N

e. 33 N

Part II: Free Response

Part 1: MCQ

1. If

*F*= 4.0 N and*m*= 2.0 kg, what is the magnitude*a*of the acceleration for the block shown below? The surface is frictionless.a.5.3 m/s2

b.4.4 m/s2

c.3.5 m/s2

d.6.2 m/s2

e.8.4 m/s2

2. The tension in a string from which a 4.0-kg object is suspended in an elevator is equal to 44 N. What is the acceleration of the elevator?

a.11 m/s2 upward

b.1.2 m/s2 upward

c.1.2 m/s2 downward

d.10 m/s2 upward

e.2.4 m/s2 downward

3. A 2.0-kg block slides on a frictionless 25° inclined plane. A force of 4.6 N acting parallel to the incline and up the incline is applied to the block. What is it’s acceleration?

a.1.8 m/s2 up the incline

b.2.3 m/s2 up the incline

c.6.6 m/s2 down the incline

d.1.8 m/s2 down the incline

e.2.3 m/s2 down the incline

4. A 1.5-kg object has a velocity of 5

**j**m/s at*t*= 0. It is accelerated at a constant rate for five seconds after which it has a velocity of (6**i**+ 12**j**) m/s. What is the magnitude of the resultant force acting on the object during this time interval?a.3.8 N

b.3.2 N

c.2.8 N

d.4.3 N

e.4.6 N

5. Only two forces act on a 3.0-kg mass. One of the forces is 9.0 N east, and the other is 8.0 N in the direction of 62° north of west. What is the magnitude of the acceleration of the mass?

a.2.0 m/s2

b.2.4 m/s2

c.3.3 m/s2

d.2.9 m/s2

e.5.7 m/s2

6. The total force needed to drag a box at constant speed across a surface with coefficient of kinetic friction

*m*k is least when the force is applied at an angle*q*such thata. sin

*q*=*m**k*.b. cos

*q*=*m**k*.c. tan

*q*=*m**k*.d. cot

*q*=*m**k*.e. sec

*q*=*m**k*.7. A 5.0-kg mass sits on the floor of an elevator that has a downward acceleration of 1.0 m/s2. On top of the 5.0-kg mass is an object of unknown mass. The force of the elevator on the 5.0-kg mass is 80 N up. Determine the unknown mass.

a. 3.3 kg

b. 2.4 kg

c. 1.6 kg

d. 4.1 kg

e. 5.0 kg

8. A block is pushed across a horizontal surface by the force shown. If the coefficient of kinetic friction between the block and the surface is 0.30,

*F*= 20 N,*q*= 30°, and*M*= 3.0 kg, what is the magnitude of the acceleration of the block?a. 2.8 m/s2

b. 2.3 m/s2

c. 1.8 m/s2

d. 3.3 m/s2

e. 5.4 m/s2

9. Two blocks in contact with each other are pushed to the right across a rough horizontal surface by the two forces shown. If the coefficient of kinetic friction between each of the blocks and the surface is 0.30, determine the magnitude of the force exerted on the 2.0-kg block by the 3.0-kg block.

a. 15 N

b. 25 N

c. 11 N

d. 22 N

e. 33 N

Part II: Free Response

- Suppose you are struggling to keep a 20.0 kg block from sliding down a 40.0o ramp. If the coefficient of static friction, μs, is a low 0.050, how much force will you need to apply to overcome the weight pulling the block down the ramp and static friction?
- An inventive child wants to reach an apple in a tree without climbing the tree. Sitting in a chair connected by a rope that passes over a frictionless pulley, he pulls on the loose end of the rope with such a force that the spring scale reads 250. N. The child's true weight is 320. N, and the chair weighs 160. N.

a) Show that the acceleration is

b) Find the force the child exerts on the chair.

3. A 2.00 kg block is given an initial speed of 2.50 m/s up a plane inclined 15.0o with the horizontal. The coefficient of kinetic friction between block and plane is 0.250. What speed does it have just as it returns to its initial position?

*upward*and find its magnitude.b) Find the force the child exerts on the chair.

3. A 2.00 kg block is given an initial speed of 2.50 m/s up a plane inclined 15.0o with the horizontal. The coefficient of kinetic friction between block and plane is 0.250. What speed does it have just as it returns to its initial position?