Answer:
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.
I believe the energy being described is the potential energy. Potential energy is the stored energy, it is the energy an object has because of its position or shape. It is also the energy possessed by an object because of its position relative to other objects, stresses within itself, its electric charge, or other factors. The major types of energy include the gravitational energy of an object that depends on its mass and its distance from the center of mass.
Answer:it causes the moving object to slow eventually stop
Explanation:
In the first law, an object will not change its motion unless a force acts on it. So I think the answer is A. Only objects that are moving.
Answer:
d. The hammer falls with a constant acceleration
Explanation:
Since gravity is the only thing that is acting on the hammer as it falls and gravity is a form of acceleration then acceleration of 9.81m/s² which is gravity is the correct answer.
