1) Read the script. A car starts 10 m north of a reference point. It moves at a constant speed over the next 5 s, reaching a position 10 m south of the reference point.
What is the average speed of the car?
0m/s
4 m/s north
2 m/s south
4 m/s south
-I know that v=d/t but I don’t know what to do after getting 2 m/sn with a position 10 m south of the reference point.
2)
A 60 kg skydiver falls at a terminal velocity of 50 m/s.
Calculate the amount of gravitational force acting on the skydiver.
3000N
9.8N
588N
0N
Could anyone help me with the equation I should do for this one?
3)
Study the scenario.
A moving block of ice begins to slide down an icy hill. The system consists of Block, Hill and Earth. (There is no friction.)
Which choice best describes changes in kinetic and potential energy?
The kinetic energy remains constant as the block moves up the hill because its speed remains constant. The potential energy increases because the height of the block relative to its starting position increases. The total energy increases.
The kinetic energy decreases as the block goes up the hill because it slows down. The potential energy increases because the height of the block relative to its starting position increases. The total energy remains constant.
The kinetic energy remains constant as the block moves up the hill because its speed remains constant. The potential energy remains constant because the block stays on the ground all the time. The total energy remains constant.
The kinetic energy increases as the block moves up the hill because it is accelerating. The potential energy increases because the height of the block relative to its starting position increases. The total energy increases.
I think it’s D, but I’m not sure.