Answer:D
Explanation:
When the character falls off from cliff he moves away from the observer as he falls down and hence the frequency heard by observer lowers as he falls.
Therefore the pitch of the sound is lower than the original sound and decreasing as he falls
Option D is the correct choice
Answer:
wood ,clay brick ,aluminum, and copper.
Explanation:
Centripetal acceleration is the acceleration of an object acted upon a force that pulls it toward the center of origin. For constant speed, there is no acceleration, since acceleration is defined as the difference of velocities at an elapsed time. Hence, if speed doubles, then the centripetal acceleration would increase as well.
Answer : The change in momentum of an object is equal to the impulse that acts on it.
Explanation :
Change in momentum : The change in momentum of an object is the product of the mass and the change in velocity of an object.
The formula of change in momentum is,

Impulse : An impulse of an object is the product of the force applied on an object and the change in time. Impulse is also equivalent to the change in momentum of an object.

Proof :

Hence, the change in momentum of an object is equal to the impulse that acts on it.