An rv is traveling 60 km/h along a highway. a boy sitting near the driver of the rv throws a ball to another boy at the back end of the rv with a speed of 25 km/h. what is the speed of the ball relative to the boys? km/h what is the speed of the ball relative to a stationary observer on the side of the road? km/h

Speed of the ball relative to the boys: 25 km/h

Speed of the ball relative to a stationary observer: 35 km/h

Explanation:

The RV is travelling at a velocity of

Here we have taken the direction of motion of the RV as positive direction.

The boy sitting near the driver throws the ball back with speed of 25 km/h, so the velocity of the ball in the reference frame of the RV is

with negative sign since it is travelling in the opposite direction relative to the RV. Therefore, this is the velocity measured by every observer in the reference frame of the RV: so the speed measured by the boys is

v = 25 km/h

Instead, a stationary observer outside the RV measures a velocity of the ball given by the algebraic sum of the two velocities:

v = +60 km/h + (-25 km/h) = +35 km/h

So, he/she measures a speed of 35 km/h.

can be answered using momentum.

momentum = p

p1= mass1 * velocity1

p1 = p2

therefore

p1 = 6kg * 4m/s

p1 = 24kgm/s

p2=m2 * v2

24 kgm/s = 7kg * v2

v2 = 24 kgm/s / 7kg

v2= 3.42 m/s

small = small current large mag large current