# physic

posted by mark

A ball is thrown straight upward and returns to the thrower's hand after 2.00 s in the air. A second ball thrown at an angle of 40.0° with the horizontal reaches the same maximum height as the first ball.
(a) At what speed was the first ball thrown?
m/s

(b) At what speed was the second ball thrown?
m/s

1. Henry

Tr = Rise time, Tf = Fall time.

a. Tr + Tf = 2 s, Tf = Tr, Tr+Tr = 2, 2Tr = 2, Tr = 1 s.

V = Vo + g*Tr = 0, Vo = -g*Tr =
9.8*1 = 9.8 m/s.

b. Yo = 9.8 m/s(Part a), Vo*sin40
= 9.8, Vo = 9.8/sin40 = 15.25 m/s.

## Similar Questions

1. ### pHYSICS

A BALL IS THROWN STRIAGHT UPWARD AND RETURMS TO THE THROWER'S HAND AFTER 3 SECONDS IN THE AIR. A SECOND BALL IS THROWN AT AN ANGLE OF 30 DEGREES WITH THE HORIZONTAL. AT WHAT SPEED MUST THE 2ND BALL BE THROWN SO THAT IT REACHES THE …
2. ### science

a ball is thrown straight upward and returns to the thrower's hand after 3.00s in the air. A second ball is thrown at an angle of 30.0 deg with the horizontal. At what speed must the second ball be thrown so that it reached the same …
3. ### Physics

A ball is thrown straight upward and returns to the thrower's hand after 3.40 s in the air. A second ball is thrown at an angle of 29.0° with the horizontal. At what speed must the second ball be thrown so that it reaches the same …
4. ### physics

A ball is thrown straight upward and returns to the thrower's hand after 2.20 s in the air. A second ball is thrown at an angle of 31.0° with the horizontal. At what speed must the second ball be thrown so that it reaches the same …
5. ### Physics

A ball is thrown straight upward and returns to the thrower’s hand after 2.90 s in the air. A second ball is thrown at an angle of 32.0 ◦ with the horizontal. At what speed must the second ball be thrown so that it reaches …
6. ### Physics

A ball is thrown straight upward and returns to the thrower’s hand after 2 s in the air. A second ball is thrown at an angle of 38 degrees with the horizontal. At what speed must the second ball be thrown so that it reaches the …
7. ### Physics

A ball is thrown straight upward and returns to the thrower's hand after 2.30 s in the air. A second ball is thrown at an angle of 42.0° with the horizontal. At what speed must the second ball be thrown so that it reaches the same …
8. ### Physics

A ball is thrown straight upward and returns to the thrower’s hand after 2.3 s in the air. A second ball is thrown at an angle of 60◦ with the horizontal. At what speed must the second ball be thrown so that it reaches the …
9. ### physics

A ball is thrown straight upward and returns to the thrower's hand after 2.00 s in the air. A second ball thrown at an angle of 40.0° with the horizontal reaches the same maximum height as the first ball. (a) At what speed was the …
10. ### Physics

A ball is tossed upward and returns to its original position after 19.7 seconds. If another ball is thrown at an angle of 41.4 degrees above the horizontal, at what speed, in m/s, must it be thrown such that it returns to the same …

More Similar Questions