2. Physics - Q&A

What work is done if a force of 100 N moves a body 15 metres?

• 150 kJ.
• 1.5 kJ.
• 0.15 J.

Fahrenheit may be converted to Celsius by using the equation

• degrees C = 5/9 * ( degrees F - 32).
• degrees C = 5/9 * ( degrees F + 32).
• degrees C = 9/5 * ( degrees F - 32).

For a car weighing 1000 N, what force would be required to accelerate the car to 3 ms-2

• 150.2 N.
• 305.8 N.
• 610.5 N.

A spring extends 7 cm to the ground and back again 20 times a minute. What is the period?

• 0.3 hertz.
• 3 seconds.
• 1/3 cycle.

For a heat pump to internally heat it uses a

• inside evaporator.
• inside condenser.
• inner evaporator.

In a heat pump

• the evaporator gains heat in cycles.
• the condenser always loses heat flow.
• the pump operates in both directions.

Given that 1 cubic foot of water weighs 62.4 lbs and the specific gravity of fuel is 0.81, what is the weight of 10 cubic foot of fuel?

• 402.8 lbs.
• 505.4 lbs.
• 624.0 lbs.

When light rays enter a medium with a different refractive index they

• split in two.
• stay aligned.
• change speed.

Material A and material B are both removed from the same oven at the same time, after being in the same amount of time. Material A is a higher temperature than material B. This is because

• material B has a higher specific heat capacity.
• material A had a higher initial oven temperature.
• material A has a higher specific heat capacity.

Ignoring friction, if you let an object slide down a slope, at the bottom

• the potential energy is equal to the kinetic energy.
• the potential energy is more than the kinetic energy.
• the kinetic energy is more than the potential energy.

A pile driver of mass 1000 kg, hits a post 3 m below it. It moves the post 10 mm. Assuming gravity = 10 m/s, what is the kinetic energy of the pile driver?

• 30 kJ.
• 45 kJ.
• 90 kJ.

A spring, operating within its elastic range, shortens by 60mm when a load of 480N is applied to it. Calculate the total shortening when the load is increased by 120N

• 82mm.
• 45mm.
• 75mm.

In a concave mirror, a light ray passing through the focal point will be reflected

• through the midpoint.
• toward the focal point
• parallel to the axis.

In a jack with a ram only on one side and hydraulic fluid applied from both sides

• the ram will remain stationary, since equal hydraulic fluid pressures cancel on both sides of it.
• the ram will move away from the side where the ram is due to pressure on differential areas.
• the ram will move to the side where the ram is, due to pressure acting on differential areas.

Brownian Movement describes

• the bonding of molecules.
• the fission of molecules.
• the motion of molecules.

When an open pipe is played and a note is heard

• the lowest frequency of the note is called second harmonic.
• resonance occurs with standing waves set up inside the pipe.
• the fundamental frequency is always twice the pipe diameter.

A ram has a piston with 2 in2. Another ram with a piston of 4 in2 will provide

• triple the force.
• double the force.
• square the force.

A drive shaft has a speed 150pi radians a second. What is the speed in RPM?

• 4500.
• 9000.
• 1500.

For a car weighing 1000 N, what force would be required to accelerate the car to 3 ms-2

• 150.2 N.
• 305.8 N.
• 610.5 N.

A mass on a spring nearly hits the ground 20 times a minute, its frequency is

• 3 cycles per second.
• 1/3 cycle per second.
• 20 cycles per second.

A temperature of 41 degrees Fahrenheit is, in Centigrade

• 7 degrees.
• 5 degrees.
• 9 degrees.

A drive shaft has a speed 150pi radians a second. What is the speed in RPM?

• 4500.
• 9000.
• 1500.

A freely falling body, falling from a height of 2km, and assuming g = 10m/s2, will strike the ground in a time of

• 40s.
• 80s.
• 20s.

In a heat pump

• the evaporator loses heat.
• the condenser loses heat.
• the compressor loses heat.

A passive sensor

• does not require power.
• requires dc excitation.
• requires ac power input.