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Two vehicles are approaching an intersection. One is a 2900-kg pickup traveling

ID: 1355649 • Letter: T

Question

Two vehicles are approaching an intersection. One is a 2900-kg pickup traveling at 11.1 m/s from east to west (the x-direction), and the other is a 1325-kg sedan going from south to north (the +y-direction at 20.4 m/s).

(a) Find the x- and y-components of the net momentum of this system.


(b) What are the magnitude and direction of the net momentum?

PART TWO:

Force of a Baseball Swing. A baseball has mass 0.145 kg.

(a) If the velocity of a pitched ball has a magnitude of 36.0 m/s and the batted ball's velocity is 58.0 m/s in the opposite direction, find the magnitude of the change in momentum of the ball and of the impulse applied to it by the bat.
13.68 kg·m/s (change in momentum)
13.68 kg·m/s (impulse)

(b) If the ball remains in contact with the bat for 2.00 ms, find the magnitude of the average force applied by the bat.

px = -32190 kg · m/s py = 27030kg · m/s

Explanation / Answer

1)
Let

m1 = 2900 kg

v1x = -11.1 m/s

m2 = 1325 kg

v2y = 20.4 m/s

Px = m1*v1x

= 2900*(-11.1)

= -32190 kg.m/s

Py = m2*v2y

= 1325*20.4

= 27030 kg.m/s

b) magnitude, P = sqrt(Px^2 + Py^2)

= sqrt(32190^2 + 27030^2)

= 42033.5 kg.m/s

direction : theta = tan^-1(Py/Px)

= tan^-1(27030/32190)

= 40 degrees west of north

2)

a) change in momentum = m*(v2 - v1)

= 0.145*(58 - (-36))

= 13.63 kg.m/s
we know, impulse = change in momentum

= 13.63 kg.m/s

b) Impulse = F*dt

==> F = impulse/dt

= 13.63/(2*10^-3)

= 6815 N