Adrian-forces and motion

The following figure shows a girl throwing a stone vertically upwards. The stone leaves her hand when it is 1 m above the ground. Then it rises to 15 m above the ground and falls onto the roof of a house. The roof of the house is 10 m high. What are the total distance travelled by the stone and its displacement for the whole journey? The horizontal motion of the stone is negligible.

• Total distance:19 upwards total displacement:9

• Total distance:20 upwards total displacement:9

• Total distance:19 upwards total displacement:10

• Total distance:20 upwards total displacement:10

The speed limit of a road, which is 2 km long, is 50 km h−1. A car travels with a varying speed and its average speed in travelling pass the road is 50 km h−1. Which of the following statements about the car must be correct?

(1) It has violated the speed limit in the journey.

(2) It takes 2.5 minutes to travel pass the road.

(3) It has speeded up in the journey.

• 2

• 1 2 only

• 1 3 only

• 1 2 3

A car moves along a straight road. It speeds up from rest from 0−10 s and slows down to a stop from 10−13 s. Which of the following statements must be correct?

(1) Its acceleration is negative from 10−13 s.

(2) The magnitude of its average acceleration is larger from 10−13 s than that from 0−10 s.

(3) Its velocity is positive from 0−10 s.

• 2 only

• 1 2 only

• 1 3 only

• 1 2 3

A bus is moving at a constant speed. Which of the following statements must be correct?

(1) Its velocity is constant.

(2) Its accelerating remains zero.

(3) Its instantaneous speed is equal to its average speed.

• 3

• 1 2 only

• 1 3 only

• None of above

Which of the following statements is incorrect about scalars and vectors?

• Scalar quantities have magnitude only and no direction.

• Vector quantities must be specified by magnitude and direction.

• Two vectors in different directions can be added to form a new vector.

• Two vectors are identical if they have the same direction.

A minibus travels at 36 km/h along a straight road. Seeing the red traffic light, the driver applies the brake. The minibus decelerates uniformly and stops after travelling for 15 m. Find the deceleration of the minibus.

• 0.46 m s–2

• 2.40 m s–2

• 3.05 m s–2

• 3.33 m s–2

equation between resultant force, mass, acceleration

• Resultant force = mass / acceleration

• Mass = acceleration / resultant force

• Acceleration = resultant force / mass

• Resultant force = mass + acceleration

Which one is non contact force?

• Pull

• Push

• Electrical

• Tension

• Friction

Which one is Hooke’s law

• F = PK

• F = Ko

• extension = force / spring constant

• Force = extension / spring constant

How to find how far has the object moved in a velocity time graph

• Length of the curve

• Area under the curve

• Area above the curve

• Y axis / X axis