9. a baseball pitcher hurls a 400 g baseball toward a batter with a speed of 30 m/s. the batter hits the pitch directly back toward the pitcher and it travels at 38 m/s. if the collision with the bat required 80 ms (milliseconds), find the force the bat applies to the ball. (watch signs.)

The force the bat applies to the ball is 340 N

Explanation:

given information:

mass of the ball, m = 400 g = 0.4 kg

initial velocity, = 30 m/s

final velocity,  = 38 m/s

time, t = 80 ms = 0.08 s

the correlation between the change in momentum and the force is shown by the following equation

ΔP = FΔt

F = ΔP/Δt

where,

Δp = mΔv

     = m()

     = m()

= - because in opposite direction, thus

F = ΔP/Δt

  = m()/Δt

   = (0.4)(38+30)/0.08

   = 340 N

the independent variable, or the one that is intentionally manipulated is the speed.