Mechanics P1

A man walks 8 m to the east followed by another 6 m to the south. What is his eastward displacement?

• 2 m

• 6 m

• 8 m

• 14 m

Answer explanation

Remember EASTWARD

A car accelerates at a rate of 5m/s2 from rest for 10s. What is its speed at the end of 10s?

• 0 m/s

• 2 m/s

• 5 m/s

• 50 m/s

Answer explanation

V_f = V_i + a.t

= 0 + 5.10 = 50 m/s

V_f : final velocity

V_i : initial velocity

a : gia tốc

t : elapsed time

A racing car accelerates uniformly along a straight road. Marker posts are placed at 100 m apart along the road. The car has a speed of 10 m/s when it passes one post, and 20 m/s when it passes the next. What is the acceleration of the car?

• 0.5 m/s^2

• 1,5 m/s^2

• 15 m/s^2

• 5 m/s^2

Answer explanation

Vf bình = Vi bình + 2a.s

20 bình = 10 bình + 2.a.100

400 = 100 + 200a

=> a = 1,5 m/s^2

A metal ball hits a sand bed one second after it is released from rest, and makes an impression 8.0 mm deep in the sand. Air resistance may be taken as negligible. What is the average deceleration of the ball on hitting the sand?

• 6.0 x 10 bình m s −2

• 1.2 x 103 m s −2

• 6.0 x 10³ m/s²

• 1.2 x 10² m/s²

A car decelerates at a rate of 5 m/s2 from an initial speed of 40 m/s. What is its speed after 6 s?

• 15 m/s
• 10 m/s
• 25 m/s
• 30 m/s

Answer explanation

v = u + at

v = 40 + (-5).6

v = 10 m/s

a = (-5) because a car is decelerate

A car has a hole in the petrol tank and petrol is dripping off the tank at a constant interval.

Which of the following statement is true about the diagram shown

• The car is moving at a constant speed

• The car is accelerating

• The car is decelerating

• The car is moving at an increasing deceleration

• 0.25 Hz

• 4 Hz

• 8 Hz

• 25 Hz

For a particle accelerating along a straight line, what is the definition of its velocity?

• Velocity is displacement divided by time

• Velocity is distance divided by time

• Velocity is the rate of change of displacement

• Velocity is the rate of change of distance

Which of the following gives the acceleration of a body?

• the area under its displacement - time graph

• the area under its velocity - time graph

• the area under its velocity - time graph

• the gradient of its velocity - time graph

The figure denotes velocity−time graph. Displacement is equal to:

• y(x1 +x2 +x3)

• y(x3 −x1)

• y(x3 −x2 −x)

• y/2 (x3 +x2 −x1)

Answer explanation