Physics
An artifical satellite is moving in a circular orbit around the Earth. Which statement is correct ?
- A force is needed to keep it moving as its speed is changing.
- No force is needed as it is in space.
- A tangential force of gravity increases its speed.
- Centripetal force due to the Earth's gravity continuously changes the direction of velocity.
Answer
Centripetal force due to the Earth's gravity continuously changes the direction of velocity.
Reason — A satellite moving in a circular orbit has constant speed but its direction of velocity keeps changing and this change in direction requires a centripetal force. The Earth’s gravitational force provides this centripetal force, continuously changing the direction of the satellite’s velocity and keeping it in orbit.
Related Questions
The direction of centripetal force is always :
- along the tangent at that point of the circular path
- towards the centre
- outwards from the centre
- none of the above
Centrifugal force is :
- a real force
- the force of reaction of centripetal force
- a fictitious force
- directed towards the centre of the circular path
Clothes in a dryer of a washing machine appear to stick to the drum walls during spinning. What provides the necessary centripetal force to keep the clothes moving in a circle.
- gravitational force
- friction between clothes
- tension in clothes
- drum wall
Assertion (A): When a beam is in static equilibrium, the sum of clockwise moments is equal to the sum of anticlockwise moments.
Reason (R): According to the principle of moments for a body in equilibrium, the sum of moments acting in one direction must be equal to the sum of moments in opposite direction.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true and R is not the correct explanation of A.
- assertion is false but reason is true.
- assertion is true but reason is false.