3.1 Mass and Weight 2021 JnN

The gravitational field strength on the Moon is smaller than that on the Earth.

A scientist examines a rock which has been brought back from the Moon.

He measures three quantities.

1. the density of the rock

2. the mass of the rock

3. the weight of the rock

Which quantities are the same size on the surface of the Earth and on the surface of the Moon?

• 1 and 2 only

• 1 and 3 only

• 2 and 3 only

• 1, 2 and 3

Which statement about the equation shown is correct?

W = mg

• g is a force, m and W are not forces.

• m is a force, g and W are not forces.

• W is a force, g and m are not forces.

• None of g, m and W are forces.

A student uses a force meter to measure the weights and a balance to measure the masses of four different objects.

He puts his measurements in a table.

Which row is correctly recorded?

An object has a weight of 6.4 N on the Earth where the gravitational field strength is 10 N/kg.

Which row states the mass and the weight of the object on the Moon where the gravitational field strength is 1.6 N/kg?

In which situation does object X have a greater mass than object Y?

• Object X is in a larger gravitational field than object Y and both have the same weight.

• Object X shows a greater resistance to change in motion than object Y and both experience the same resultant force.

• Object X has a lower density than object Y and both occupy the same volume.

• Object X moves at a greater speed than object Y and both possess the same kinetic energy.

Which statement about mass and weight is correct?

• Mass is a property that causes change in motion.

• Mass is caused by a gravitational field acting on a weight.

• Weight is a property that resists change in motion.

• Weight is caused by a gravitational field acting on a mass.

Two stones of different weights fall at the same time from a table.

Air resistance may be ignored.

What will happen and why?

• Both stones hit the floor at the same time.

  Acceleration of free fall is constant.

• Both stones hit the floor at the same time.

  They fall at constant speed.

• The heavier stone hits the floor first. Acceleration increases with weight.

• The heavier stone hits the floor first. Speed increases with weight.

Which statement gives the correct relation between m1, m2 and m3?

• m1 is equal to m2 and m2 is equal to m3.

• m1 is greater than m2 and m2 is greater than m3.

• m1 is less than m2 and m2 is greater than m3.

• m1 is less than m2 and m2 is less than m3.

On Mars, the acceleration of free fall g is 3.7 m/s².

What is the weight of a 2.0 kg mass on Mars?

• 0.54 N

• 1.9 N

• 7.4 N

• 20 N

An astronaut wants to know how much she would weigh on different moons. She measures her mass on Earth to be 82 kg. She researches the values of g on different moons and uses these values to calculate her weight. The results are shown. Which weight is calculated correctly?