Topic Quiz on Circular Motion
Quiz
Which one of the following statements about circular motion is correct?
- The speed is changing all the time.
- The linear speed is constant but the acceleration is changing all the time.
- The linear speed is constant and the velocity is constant.
- The linear speed is constant but there is acceleration because the velocity is changing all the time, since there is a constant change in direction.
Which one is correct about the centripetal force?
- It is inversely proportional to the velocity.
- It always acts at 90 degrees to the velocity, and away from the centre of the circle
- It always acts at 90 degrees to the velocity, and towards the centre of the circle
- It is balanced by the centrifugal force
A model aeroplane is tethered to a post and held by a fine line. It flies in a horizontal circle. Then the line breaks. What direction will it fly in?
- Directly to the centre of the circle.
- Directly away from the centre of the circle.
- In a circular path, as before
- In a straight line at a tangent.
A satellite is in orbit. This is because:
- There is no gravity.
- The satellite is being held there by centrifugal force.
- Gravity is acting as a centripetal force.
- It is being attracted by the gravity of other objects in space.
Centripetal force can be worked out with the relationship
- F = v^2/r
- F = mv^2/2
- F = mv^2/r
- F = mr^2/v
Which one of the following statements is correct when a mass is made to move in a vertical circle
- The tension in the string is greatest at the bottom of the circle and least when at the top.
- The tension in the string is greatest at the top of the circle and least when at the bottom.
- The tension is provided by a combination of centrifugal force and weight.
- The weight acts in a direction away from the centre of the circle.
Angular velocity is measured in:
- Metres per second
- Degrees per second
- No units at all
- Radians per second
Angular velocity is used in preference to speed because:
- The speed depends on the radius.
- The centripetal force acts at 90 degrees to the speed.
- The speed does not change.
- Speed is harder to measure.
A car goes around a bend. What provides the centripetal force?
- Gravity
- Friction
- Electrostatic attraction
- No force at all.
A girl of mass 30 kg is on a roundabout of radius 5 m that makes one complete turn every 5 seconds. What is the centripetal force acting on her?
- 38 N
- 47 N
- 236 N
- 300 N