Weight and Circular Motion

Question 1

What is meant by the weight of an object?

Answer 1

The force acting on an object due to gravity

Question 2

What is a calibrated spring balance used to measure?

Answer 2

Weight or force

Question 3

What’s the formula for calculating the weight of an object?

Answer 3

Weight = mass x gravitational field strength or W = m x g

Question 4

An object weighs 33 N. The object triples in mass and stays in the same place. What will its new weight be?

Answer 4

99 N
Weight and mass are directly proportional when g is constant, so if the mass triples the weight will triple also: 3 x 33 = 99 N

Question 5

The Moon has a gravitational field strength of approximately 1.6N/kg. Calculate the weight of a 10 kg teddy bear on the Moon.

Answer 5

16N

W = m x g so the weight of the teddy bear = 10 x 1.6 = 16 N

Question 6

a 3 kg piece of broken spaceship weighs 12 N on a planet. Work out the gravitational field strength of the planet.

Answer 6

4 N/kg

g = W / m so g = 12 / 3 = 4N/kg

Question 7

For circular motion, in which direction does the centripetal force act?

Answer 7

Towards the centre of the circle

Question 8

Explain why the Moon has a constant speed but its velocity is constantly changing

Answer 8

The velocity of an object is its speed in a given direction. The Moon orbits the Earth in a circular orbit. As it moves in a circle, its direction of motion is constantly changing, so its velocity must also be constantly changing