# Exercises - Force and Motion 6

1. Given that the gravitational field strength on the Earth and Moon is 9.81 Nkg-1 and 1.64 Nkg-1 respectively, If the weight of an object is 2943N on the earth, what is its weight on the Moon?
1. 492.0 N
2. 482.7 N
3. 300.0 N

2. An object is falling in a vacuum. Which of the following quantities of the object does not change?
1. Momentum
2. Acceleration
3. Velocity

3. A stone is thrown vertically upwards from a ground with an initial velocity of 15 ms-1. If air resistance can be neglected, find the time taken for the ball to reach to the maximum height

4. The diagram shows a man standing on a balance inside a lift. If the mass of the man (with his bag and umbrella) is 75kg, find the reading of the balance when the lift is moving downward at a deceleration of 8ms-2.

5. The diagram shows a man standing on a balance inside a lift. If the mass of the man (with his bag and umbrella) is 75kg, find the reading of the balance when the lift is moving upward at a deceleration of 2 ms-2.

6. The figure below shows two vectors, P and Q are acting on an object, O. A student would like to determine the resultant vector of P and Q. Among the diagrams below, which one shows the correct drawing of the addition of the vectors?
A.
B.
C.
D.

7. Diagram below shows 2 forces at right angle. Find the magnitude of the resultant force produced by the 2 forces.
1. 7 N
2. 17 N
3. 13 N

8. Three forces are acting on a wooden block as shown bwlow. What is the magnitude of the resultant force?
1. 13 N
2. 12 N
3. 10 N
4. 15 N

9. Figure below shows a block of mass 2 kg pulled by a 30N force at an angle 60° from the horizontal. If the friction between the block and the table is 5N, what is the net force acting on the block?
1. 5 N
2. 15 N
3. 10 N
4. 20 N

10. Figure below shows a block of mass 2 kg pulled by a force F at an angle 60° from the horizontal. The friction between the block and the table is 5N. Find the magnitude of F if the block is moving at a uniform velocity 2 ms-2.
1. 18 N
2. 4 N
3. 9 N
4. 13 N