Question

A stone is thrown at an angle of 20° below the horizontal from the top of a cliff. Assume no air resistance. One second after being thrown, the stone's acceleration makes an angle θ below the horizontal. Which is true?

Answer 1

A stone is thrown from a cliff at 20°below the horizontal. The stone moves in a plane with both horizontal and vertical components of velocity. Acceleration of an object is defined as the change in velocity with respect to the time.

 

The horizontal component of velocity is remains constant and the vertical component of velocity varies throughout the motion of the stone. The acceleration of the object is zero in horizontal direction and the object accelerates in vertical due to gravity. Thus, the horizontal component of acceleration is zero and stone have only vertical component of vertical acceleration and it is due to gravity. Hence, the direction of acceleration is 90°below the horizontal.

 

Therefore, the correct option is (e).

Therefore, the correct option is (e).