Answer:
2 a) it is less dense than the water
2 b) it is more dense than the water
3 a ping pong ball is hollow and less dense than the water so it quickly bounces up to the surface of the water
You have to divide 3000 miles with the 5 and it gives you a velocity of 600
Answer:
9.8 Joules (rounded to 2 significant figures)
Explanation:
Work done (J)= Force(N) x distance changed (m)
- Force= 9.80665 x 0.5kg
- Force= 4.90332 Newtons
- Distance changed= 5-3
- distance changed= 2m/s
--> work done= 4.90332 x 2
work done= 9.8 Joules
The block moves with constant velocity: for Newton's second law, this means that the resultant of the forces acting on the block is zero, because the acceleration is zero.
We are only concerned about the horizontal direction, and there are only two forces acting along this direction: the force F pushing the block and the frictional force

acting against the motion. Since their resultant must be zero, we have:

The frictional force is

where

is the coefficient of kinetic friction

is the weight of the block.
Substituting these values, we find the magnitude of the force F: