Aball is launched with an initial velocity of 28.5 m/s at a 45° angle from the top of a cliff that is 10.0 m above the water below. use g = 9.80 m/s2 to simplify the calculations. note: you could answer these questions using projectile motion methods, but try using an energy conservation approach instead.

(a) what is the ball's speed when it hits the water?
m/s

(b) what is the ball's speed when it reaches its maximum height?
m/s

(c) what is the maximum height (measured from the water) reached by the ball in its flight?
m

2.

a boy reaches out of a window and tosses a ball straight up with a speed of 15 m/s. the ball is 30 m above the ground as he releases it. use energy to find the following.

(a) what is the ball's maximum height above the ground?
m

(b) what is the ball's speed as it passes the window on its way down?
m/s

(c) what is the speed of impact on the ground?

Explanation:

When it hits the water , the initial kinetic energy will increase by additional potential energy of mgh where h is 10 m .

Initial kinetic energy

= 1/2 x m x (  28.5 )²

= 406.125 m

Extra potential energy added

= m x 9.8 x 10

= 98m

Total energy

= 504.125 m  J

If v the the velocity at the bottom

1/2 m v² = 504.125 m

v =  31.75 m/s

b ) The velocity at the top  will be equal to the horizontal component of initial velocity

= 28.5 cos 45

= 20.15 m /s

c ) kinetic energy at the top

= 1/2 m x( 20.15 )²

= 203 m

Loss of energy at the top

= 406.125  m - 203 m

= 203.125 m

This energy has been converted into potential energy

mgH = 203 m

H = 203 / 9.8

= 20.71 m

explanation: magnetic pole, region at each end of a magnet where the external magnetic field is strongest. the south-seeking pole, or any pole similar to it, is called a south magnetic pole. unlike poles of different magnets attract each other; like poles repel each other.

explanation:

earth's surface is mainly heated by the absorption of infrared radiation from the sun.

evaporation occurs because molecules in liquid water are warmed ( usually by the sun) and vibrate quicker, becoming less dense and rise.

condensation occurs because molecules in water vapor are cooled and therefore vibrate more slowly thus becoming more dense and eventually fall to earth.

lines of equal barometric pressure on a weather map are called: isobars : lines of equal temp on a weather map are called: isotherms.​