# Physic

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A ball is thrown vertically upward with a speed of +12.0m/s.
A. how long the ball take to hit the ground after it reaches it highest point?
B. What is its velocity when it returns to the level from with it started?

• Physic -

A tortoise can run with a speed of 0.12m/s and a hare can run 20 times as fast. In a race, they both start at the same time, but the hare stops to rest for 2.0 minutes. The tortoise wins by a shell(25cm).
A. how long does the race takes?
B. What is the length of race?

• Physic -

Please post one question at a time.

The speed when the ball hits the ground will again be 12 m/s (because of conservation of energy), but the direction will be reversed, making it -12.0 m/s.

The time of flight AFTER reaching max height will be the time it takes to accelerate to a speed of 12 m/s, which is 12/g = 12/9.8 s.

• Physic -

A tortoise can run with a speed of 13.0 cm/s, and a hare can run 20 times as fast. In a race, they both start at the same time, but the hare stops to rest for 5.0 minutes. The tortoise wins by a shell (40 cm).
(a) How long does the race take?
s
(b) What is the length of the race?
m