Fizzix Kwiz!

Which instrument is used to measure accurately the diameter of a thin metal wire?

• 30 cm ruler

• measuring tape

• metre rule

• micrometer screw gauge

A parachutist is falling through the air at terminal velocity.

Which statement about the parachutist is correct?

• Every force acting on the parachutist is equal to zero and his acceleration is equal to zero.

• Every force acting on the parachutist is equal to zero and his velocity is equal to zero.

• The resultant force acting on the parachutist is equal to zero and his acceleration is equal to zero.

• The resultant force acting on the parachutist is equal to zero and his velocity is equal to zero.

A stone of mass 0.12 kg is fired from a catapult. The velocity of the stone changes from 0 to 5.0 m / s in 0.60 s.

What is the average resultant force acting on the stone while it is being fired?

• 1.0 N

• 2.5 N

• 3.6 N

• 8.3 N

A ball of mass 0.16 kg is moving forwards at a speed of 0.50 m / s. A second ball of mass 0.10 kg is stationary. The first ball strikes the second ball. The second ball moves forwards at a speed of 0.50 m / s.

What is the speed of the first ball after the collision?

• 0.0 m / s

• 0.19 m / s

• 0.31 m / s

• 0.50 m / s

A ball is at rest at the top of a hill. It rolls down the hill. At the bottom of the hill the ball hits a wall and stops.

Which energy changes occur?

• gravitational potential energy → internal energy → kinetic energy

• gravitational potential energy → kinetic energy → internal energy

• kinetic energy → gravitational potential energy → internal energy

• kinetic energy → internal energy → gravitational potential energy

A student cycles along a level road at a speed of 5.0 m / s.

The total mass of the student and bicycle is 120 kg. The student applies the brakes and stops. The braking distance is 10 m.

What is the average braking force?

• 150 N

• 300 N

• 15 000 N

• 30 000 N

A submarine is 20 m below the surface of the sea. The pressure due to the water at this depth is P.

On another day, the submarine is 26 m below the surface of fresh water.

The density of sea water is 1.3 times the density of fresh water.

What is the pressure due to the fresh water at a depth of 26 m?

• P / 1.3

• P

• 1.3 P

• 1.7 P

Which quantity does not change when there is an increase in temperature?

• the density of a steel block

• the diameter of the hole in a metal nut

• the length of an iron rod

• the mass of a metal coin

A thermocouple is used to measure temperature.

Which is an advantage of using a thermocouple instead of a liquid-in-glass thermometer?

• It can measure temperature in the range –10 °C to 110 °C.

• It can measure temperature that changes rapidly.

• It has a linear scale.

• It is more sensitive.

A block of copper has a mass of 2.0 kg.

The block of copper absorbs 12 000 J thermal energy.

The specific heat capacity of copper is 385 J / (kg °C).

What is the temperature rise of the copper?

• 15.6 °C

• 31.2 °C

• 46.8 °C

• 62.4 °C