Kinematics

The diagram shows the speed-time graph for the motion of a boy on a skateboard.

Which answer describes his motion for each 5 second part?

• 0 to 5 s: non uniform acceleration

  5s to 10s: rest

  10s to 15s: uniform acceleration

  15s to 20s: constant speed

• 0 to 5s: non uniform acceleration

  5s to 10s: constant speed

  10s to 15s: uniform acceleration

  15s to 20s: at rest

• 0 to 5s: uniform acceleration

  5s to 10s: at rest

  10s to 15s: non uniform acceleration

  15s to 20s: constant speed

• 0 to 5s: uniform acceleration

  5s to 10s: constant speed

  10s to 15s: non uniform acceleration

  15s to 20s: at rest

The speed-time graph is for a car initially at rest.

The car starts to move.

Which correctly describes the car's subsequent motion?

• moving with non-uniform acceleration and then moving with uniform acceleration

• moving with uniform acceleration and then moving with non-uniform acceleration

• moving with uniform speed and then moving with non-uniform acceleration

• moving with uniform speed and then moving with uniform acceleration

The diagram shows a speed-time graph.

In which region is the acceleration decreasing?

• V to W

• W to X

• X to Y

• Y to Z

The speed-time graph is for a parachutist leaving an aircraft and falling to earth.

At which point does the parachute open?

• A

• B

• C

• D

A car takes 60 minutes to travel 100 km along a main road and then 30 minutes to travel 20 km along a side road.

What is the average speed of the car for the whole journey?

• 40 km/h

• 70 km/h

• 80 km/h

• 100 km/h

A car moving at 40 km/h speeds up with constant acceleration for 3 minutes, reaching a final speed of 80 km/h.

What is the distance travelled during this time?

• 6.0 km

• 4.0 km

• 3.0 km

• 2.0 km

What is used to calculate the value of a uniform acceleration?

• area under a speed-time graph

• change in speed / time taken

• change in velocity / time taken

• gradient of a distance-time graph

Two runners, X and Y, are in a race. The diagram shows a speed-time graph for the two runners.

Which statement is correct?

• After 8.0 s, runner X has travelled 32 m further than runner Y.

• After 8.0 s, runner Y has travelled 4.0 m further than runner X.

• The runners have travelled the same distance after 4.0 s.

• The runners have travelled the same distance after 7.0 s.

A strip of paper tape is pulled by a toy car under a vibrating arm. The arm vibrates at a rate of 50 dots per second.

The average speed of the toy car is ………………….. .

• 0.011 m/s

• 1.1 m/s

• 3.0 m/s

• 300 m/s

In the 28th SEA Games, Shanti Pereira ran at a constant rate of 5 m/s before she accelerated at a rate of 1 m/s2 in the last 4 s of her 200 m race.

What was the distance at which Shanti ran while she was accelerating?

• 8 m

• 28 m

• 50 m

• 56 m