Answer:
Explanation:
Work done by the spring is negative .
Work done by force F creating displacement d is given by the following expression .
Work = F x d
Both force and displacement are vector quantity .
When direction of force and direction of displacement is same , work is positive . When direction of force and direction of displacement is opposite , work is negative .
When spring is compressed , it exerts a restoring or opposing force in a direction opposite to the direction of displacement of box . Hence here force is opposite to displacement . Restoring force acts opposite to displacement . Hence work done by spring on box is negative .
Answer:
Water can spread germs through bacteria.
Explanation:
Bacteria can live in water and can spread to new locations when water is moved.
Answer:
Yes – its direction is changing.
Explanation:
It is given that, a car rounds a curve while maintaining a constant speed. We know that on a circular curve, the object moves with constant speed. The velocity of object keeps on changing due to change in its direction. Here, the forces acting on the car are force of gravity and the centripetal force.
We can say that yes there is a net force on the car as it rounds the curve due to the change in its direction of motion. Hence, the correct option is (3).
Answer:
C. rollback
Explanation:
The retina of the eye is located inside the eye making it impossible for the retina to roll back. Only the eye itself can rollback.