Agirl throws a ball of mass 0.8 kg against a wall. the ball strikes the wall horizontally with a speed of 11 m/s, and it bounces back with this same speed. the ball is in contact with the wall 0.05 s. what is the average force exerted on the wall by the ball?

F = 352 N

Explanation:

we know that:

F*t = ΔP

so:

F*t = M-M

where F is the force excerted by the wall, t is the time, M the mass of the ball, the final velocity of the ball and the initial velocity.

Replacing values, we get:

F(0.05s) = (0.8 kg)(11m/s)-(0.8 kg)(-11m/s)

solving for F:

F = 352 N

the minimum amperage that the current in this wire would have to have so that its weight is completely supported by the magnetic force due to earth's field, assuming that no other forces except gravity act on it

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2