Which expression has the same SI base units as pressure?

• $\frac{force}{length\ \ \times\ speed}$

• $\frac{force}{length\ \ \times\ \ time}$

• $\frac{mass}{length\ \ \times\ \ \left(time\right)^2}$

• $\frac{mass\ \ \times\ \ \left(time\right)^2}{length}$

What is an approximate value for the speed of sound in air?

• 30ms^–1

• 300ms^–1

• 30,000ms^–1

• 300,000,000ms^–1

A pendulum bob is held stationary by a horizontal force H. The three forces acting on the bob are

shown in the diagram.

The tension in the string of the pendulum is T. The weight of the pendulum bob is W. The string is held at an angle of 30° to the vertical.

Which statement is correct?

• H = T cos 30

• T = H sin30

• W = T sin30

• W = T cos 30

A student is investigating an electrical signal using a cathode-ray oscilloscope (c.r.o).

The frequency of the signal is 50kHz.

Which time-base setting on the oscilloscope should be used?

• 50mscm^–1

• 1mscm^–1

• 10µscm^–1

• 0.5 µscm–1

A student wishes to measure a distance of about 10cm to a precision of 0.01cm.

Which measuring instrument should be used?

• meter rule

• micrometer

• tape measure

• vernier calipers

An aircraft, initially stationary on a runway, takes off with a speed of 85kmh^–1 in a distance of no

more than 1.20km.

What is the minimum constant acceleration necessary for the aircraft?

• 0.23ms^–2

• 0.46ms^–2

• 3.0 ms^–2

• 6.0 ms^–2

The acceleration of free fall on Pluto is 0.66ms–2.

An object weighs 6.0N on Earth.

What would this object weigh on Pluto?

• 0.40N

• 0.93N

• 4.0 N

• 39N

A radio-controlled toy car travels along a straight line for a time of 15s.

The variation with time t of the velocity v of the car is shown.

What is the average velocity of the toy car for the journey shown by the graph?

• –1.5ms^–1

• 0.0ms^–1

• 4.0ms^–1

• 4.5ms^–1

Water flows out of a pipe and hits a wall
When the jet of water hits the wall, it has horizontal velocity v and cross-sectional area A.
The density of the water is ρ. The water does not rebound from the wall.What is the force exerted on the wall by the water?

•  $\frac{\rho v}{A}$  

•  $\frac{\rho v^2}{A}$  

•  $\rho Av$  

•  $\rho Av^2$  

A stationary firework explodes into three pieces. The masses and the velocities of the three

pieces immediately after the explosion are shown.

What are speed v₁ and speed v₂ respectively?

• 4.0, 4.0

• 9.2, 9.2

• 14,14

• 16,16