The correct choice is D .
Answer:
a) I = 13.38 kg m / s, b) F = 1,373 10³ N
Explanation:
The impulse is given by the relation
I = ∫ F dt = Δp
I = p_f -p₀
I = m (v_f - v₀)
take the ball's exit direction as positive, whereby the ball velocities
v₀ = -90mph, the final velocity v_f = + 54 m / s
Let's reduce the units to
I = 0.142 [54- (-40.23) ]
the SI system
v₀ = - 90 mph (1609.34 m / 1 mile) (1h / 3600 s = -40.23 m / s
m = 142 g (1kg / 1000) = 0.142 kg
we calculate
I = 0.142 [54- (-40) ]
I = 13.38 kg m / s
b) let's use the definition of momentum
I = ∫ F .dt
I = F ∫ dt
F = I / t
F = 13.38 / 0.008
F = 1,373 10³ N
The net force on an object subject to friction is equal to the sum of the applied force and the frictional force.
Mathematically,
Here, m is mass of object and a is its acceleration. We take frictional force negative because it opposes the motion of object.
Given, 
, 
and 
Substituting these values in above formula, we get
.
Thus, the acceleration of an object is 
Answer:
Frequency describes the number of waves that pass a fixed place in a given amount of time.
