PHY_10_V2_DM_Revision term 1 (5)

Kinematics:

1.      A tennis ball is thrown straight up and caught at the same height. Which of the following can describe the motion of the ball when it reaches the apex?

(A) The velocity of the ball is zero.

(B)  The acceleration of the ball is zero.

(C)  The acceleration of the ball is 9.8 m/s² down

(D) The acceleration of the ball is 9.8 m/s² up.

2.      The position, velocity and acceleration as a function of time of a moving object are presented by the graph. Which of the following could be used to describe this type of motion?

(A) The object accelerates from rest at a constant rate.

(B)  The object slows down at a constant acceleration.

(C)  The object is thrown straight up.

(D) The object slides up and down the frictionless inclined plane.

3.      The velocity as a function of time of two moving objects is presented by the graph above. Which of the following is true?

(A) At time t₀ object I is behind object II

(B)  At time t₀ object II is behind object I

(C)  Object I has a greater acceleration than object II

(D) Object II has a greater acceleration that object I

Dynamics:

4.      If forces F1 and F2 are forces with which two bodies interact with each other, then according to the third Newton's law:

a.       F₁ = F₂

b.      F₁ = –F₂

c.       F₁ – F₂ = ma

d.      F₁ – F₂ = ma

5.      The body moves uniformly on a horizontal surface under the action of a horizontal force, the modulus of which is 26 N. What is the magnitude of the friction force acting on the body? 26 Н

6.      A small coin lies on the rough surface of a horizontal disk, which rotates uniformly around a vertical axis passing through the center of the disk, with an angular velocity of 4 rad / s. The maximum distance between the center of the coin and the axis of rotation, at which the coin does not slide over the disk, is 15 cm. What is the coefficient of sliding friction between the coin and the surface? 0,24

7.      Two bodies connected by a weightless inextensible thread are on a smooth horizontal surface. An external horizontal force acts on the first body, the modulus of which is 63 N; the second is an external horizontal force, the modulus of which is 53 N. The masses of the bodies are 6 and 9 kg, respectively. What is the modulus of the tension force of the thread? 59 Н

Momentum:

8.      A spinning star begins to collapse under its own gravitational pull.  Which one of the following occurs as the star becomes smaller?

a.       The star’s angular velocity decreases.

b.      The star’s angular momentum remains constant.

c.       The star’s angular momentum increases.

d.      The star’s angular velocity remains constant.

e.       Both the star’s angular momentum and its angular velocity remain constant.

9.      A spinning skater draws in her outstretched arms thereby reducing her moment of inertia by a factor of 2.  Determine the ratio of her final kinetic energy to her initial kinetic energy.

a.       0.5                               (c)  2                                        (e)  16

b.      1                                  (d) 4

Hydrostatic Pressure:

1.      Find the ratio of the depth of the lowest gauge to the highest gauge.

Pascal’s Law:

1.      The pressure of the air above the water in the tank above is increased by 5 Pa.  What will each pressure gauge now read?

2.      A hydraulic lift has two connected pistons with cross-sectional areas 25 cm2 and 430 cm2. It is filled with oil of density 500 kg/m³. What mass must be placed on the small piston to support a car of mass 1300 kg at equal fluid levels?

Archimedes’ Principle:

1.      Explain why a boat made of metal is in equilibrium when stationary or floating on water.  The buoyant force pushing up on the boat is equal to the weight of the boat because the weight of the water displaced by the boat is equal to the weight of the boat.

2.      A metal box of mass 68 kg has dimensions 50 mm x 600 mm x 900 mm.

a)      Calculate the density of the material of the box. 

b)      If the box is hung from a dynamometer and placed in water, what will the dynamometer read? If placed in gasoline?  

The densities of water and gasoline are 1000 kg·m^-3 and 820 kg·m^-3, respectively.

3.      Consider two identical pails of water filled to the brim. One pail contains only water, the other has a piece of wood floating in it. Which pail has greater weight?  The weight of each pail is the same.