Physics STPM Sem 1 (Set A)

Two forces, $\overrightarrow{P\ }$  and  $\overrightarrow{Q\ }$ , act on a point as shown in the diagram above.Which vector diagram shows the correct resultant force,  $\overrightarrow{F\ }$ , acting on the point?

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A boy releases a small stone from rest at a height of 15 m from the ground. After 1.0 s, he throws another small stone straight down with an initial speed. If the two stones reach the ground at the same time, what is the initial speed of the second stone?

• 10 m s^-1

• 13 m s^-1

• 16 m s^-1

• 30 m s^-1

The particle P moves with constant velocity and collides head-on with particle Q which is stationary. After the collision, both particles move with the same velocity. Which statement is true about the collision?

• The increase in momentum of particle Q is equal to the decrease in momentum of particle P.

• The increase in kinetic energy of particle Q is equal to the decrease in kinetic energy of particle P.

• The total kinetic energy after the collision of particles P and Q is bigger than the total kinetic energy before the collision.

• The force acted by particle Q on particle P is less than the force acted by particle P on particle Q during the collision.

An object of mass 0.35 kg is pulled from rest along the rough surface of a table by a horizontal force of 5.0 N. If the velocity of the object is 4.0 m s^-1 after it moves 1.2 m, what is the coefficient of friction between the object and the surface of the table?

• 0.05

• 0.78

• 1.41

• 2.14

A body moves in a straight line from rest on a smooth horizontal surface when a constant force acts on it. Which graphs shows the variation of work done, W, with time, t, for the motion?

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Two objects, P and Q, perform circular motions at different constant speeds with radius R and 2R respectively. The mass of P is 2m while that of Q is 3m. If the centripetal forces of both objects are the same, what is the ratio of speed of P to that of Q?

•  $\frac{3}{8}$  

•  $\frac{\sqrt{3}}{2}$  

•  $\frac{2\sqrt{3}}{3}$  

•  $\sqrt{3}$  

A satellite is said to be geosynchronous if it appears to remain over a fixed position on the Earth. Which statement is not true about the geosynchronous satellite?

• The satellite completes its orbit in 8.6 x 10⁴ s.

• The satellite can be placed in any chosen orbit depending on its size.

• The satellite moves around the Earth in the same direction as the rotation of the Earth about its axis.

• The satellite moves around the Earth in the circular orbit under the influence of the gravitational force.

A satellite is moved from orbit S to orbit T as shown in the diagram above. Which is true about the energy of the satellite when it moves from orbits S to T?

• An increase in potential energy because work is done against gravity.

• A loss in potential energy because work is done against gravity.

• An increase in potential energy because work is done by the gravitational field.

• A loss in potential energy because work is done by the gravitational field.

A diver of weight 500 N stands on the free end of a uniform spring board of length 2.0 m as shown in the diagram above. Two supports, X and Y, which are separated at a distance of 0.50 m to enable the system to be in static equilibrium. If the weight of the spring board is 200 N, what are the magnitudes and directions of the reaction forces acts on the board by X and Y?

• Reaction Force of X : Magnitude = 700 N, Direction = Upward

  Reaction Force of X : Magnitude = 1400 N, Direction = Downward

• Reaction Force of X : Magnitude = 700 N, Direction = Downward

  Reaction Force of X : Magnitude = 1400 N, Direction = Upward

• Reaction Force of X : Magnitude = 1700 N, Direction = Upward

  Reaction Force of X : Magnitude = 2400 N, Direction = Downward

• Reaction Force of X : Magnitude = 1700 N, Direction = Downward

  Reaction Force of X : Magnitude = 2400 N, Direction = Upward

A uniform metal rod of length L, a cross-sectional area A and the Young's modulus E are acted by a tensile force F. The strain energy stored in the rod is represented by

• $\frac{F^2}{EA^2}$

• $\frac{F^2L}{EA}$

• $\frac{F^2}{2EA^2}$

• $\frac{F^2L}{2EA}$