Abaseball of mass 0.25 kg is hit at home plate with a speed of 40 m/s. when it lands in a seat in the left-field bleachers a horizontal distance 120 m from home plate, it is moving at 30 m/s. if the ball lands 20 m above the spot where it was hit, how much work is done on it by air resistance?

the work done by air resistance is 38.5 J

Explanation:

given information:

mass of the ball, m = 0.25 kg

initial speed, = 40 m/s

final speed, = 30 m/s

horizontal distance, x = 120 m

Δh = 20 m

according to conventional energy

W = -

where

is initial energy

 is final energy

E = KE + PE

KE is kinetic energy

PE is potential energy

W = -

   = mg + - (mg + )

   = mg( )+

   = m (gΔh + )

   = 0.25 ( (9.8) (20) + )

   = - 38.5 J

b.transmitters send radio waves, and receivers capture radio waves.

ok

explanation: