A stream is flowing at 0.75ms\(^{-1}\) and a boat heading perpendicular for the stream landed at the opposite bank at an angle of 30°. Calculate the velocity of the boat.
- A. 1.50ms-1
- B. 1.00ms-1
- C. 0.86ms-1
- D. 0.65ms-1
A catapult used to hold a stone of mass 500g is extended by 20cm with an applied force F. If the stone leaves with a velocity of 40m/s, the value of F is
- A. 4.0 x 102N
- B. 2.0 x 103N
- C. 4.0 x 103N
- D. 4.0 x 104N
If the force and the velocity on a system are each reduced simultaneously by half, the power of the system is
- A. doubled
- B. reduced to a quarter
- C. reduced by half
- D. constant
At a fixed point below a liquid surface, the pressure downwards is P1 and pressure upwards is P2. It can be deduced that?
- A. P1 > P2
- B. P1 ≥ P2
- C. P1 < P2
- D. P1 = P2
The velocity ratio of a machine is 5 and its efficiency is 75%. What effort would be needed to lift a load of 150N with the machine?
- A. 20N
- B. 30N
- C. 40N
- D. 50N
I. Its velocity is constant
II. No work is done on the body
III. It has constant acceleration directed away from the centre
IV. The centripetal force is directed towards the centre
Which combination of the above is true of a body moving with constant speed in a circular track?
- A. II and IV
- B. I and IV
- C. II and III
- D. I and III
When a ship sails from salt water into fresh water, the fraction of its volume above the water surface will
- A. increase
- B. decrease
- C. remain the same
- D. increase then decrease