A ball is thrown at an original speed of 8.0 m/s at an angle of 35° above the horizontal.If there is no air resistance,what is the speed of the ball when it returns to the same horizontal level?
A)4.0 m/s
B)8.0 m/s
C)16 m/s
D)9.8 m/s

Question

Quizplus · Accepted Answer

When the ball is thrown, it has a horizontal component of velocity given by Vx = V0cos(theta) = 8.0cos(35) = 6.57 m/s, and a vertical component of velocity given by Vy = V0sin(theta) = 8.0sin(35) = 4.57 m/s (taking upwards as positive).

At the highest point of its trajectory, the vertical component of velocity becomes zero, and the horizontal component remains constant throughout. Therefore, the speed of the ball when it returns to the same horizontal level is equal to the initial horizontal speed, which is 6.57 m/s (or approximately 8 m/s).

Note that gravity does not affect the horizontal component of velocity, so the horizontal speed remains constant. The vertical speed, however, is affected by gravity, which causes it to decrease to zero at the highest point and then increase again in the downward direction.

A Ball Is Thrown at an Original Speed of 8