Mechanics | Relativity Answers

A tennis ball is dropped from a height of 7 m and rebounds to a height of 3 m. If it is in contact with the floor for 0.029 s, what is the average acceleration during this period?

A cyclist is initially moving at 15 m/s. He covers 45 m in the next 4.8s. Find:
a) his acceleration
b) his speed after 4.8 s

A car moving at 95 km/h meets a train of length 1.2 km moving at 40 km/h along a track parallel to the road. What distance does the car travel in passing the length of the train given that they travel
a) in the same direction
b) in opposite direction

I found the answer when they travel in the same direction wich gave me 2.07 km, but I tried in opposite direction and I can't seem to have the right answer.

The two ends of a train moving with constant acceleration pass a certain point with velocities u and 3u. The velocity with which the middle point of the train pared passes the same point is
(1)2u
(2)3/2u
(3)√5u
(4)√10u

A particle starts moving with acceleration 2m/sec². Distance travelled by it in 5th half second is
(1)1.25
(2)2.25
(3)6.25
(4)30.25
All are in meter

If a ball is thrown vertically upwards with speed u, the distance covered during the last t sec of its ascent is
(1)ut
(2)1/2gt²
(3)ut-1/2gt²
(4)(u+gt)t

On her way to visit grandmother, Red Riding Hood sat down to rest and placed her 1.2-kg basket of goodies beside her. A wolf came along, spotted the basket, and began to pull on the handle with a force of 6.4 N at an angle of 25 degrees with respect to vertical. Red was not going to let go easily, so she pulled on the handle with a force of 12 N. If the net force on the basket is straight up, at what angle was Red Riding Hood pulling?

A sailor goes 8 km downstream in 40 minutes and returns in 1 hour. Determine the speed of the sailor in still water and the speed of the current.

You started to run at 10 km/h when you left your house and you arrived at school 30 minutes later. Assuming that your average acceleration was 30 km/h^2, how fast were you running when you arrived?

You throw a ball from the balcony onto the court in the basketball arena. You release the ball at a height of 6 m above the court, with an initial velocity equal to 9 m/s at 33° above the horizontal. A friend of yours, standing on the court 10 m from the point directly beneath you, waits for a period of time after you release the ball and then begins to move directly away from you at an acceleration of 3 m/s2. (She can only do this for a short period of time!) If you throw the ball in a line with her, how long after you release the ball should she wait to start running directly away from you so that she'll catch the ball exactly 1 m above the floor of the court?