Question

Prof. Dink is having a nightmare where she fonds herself snowboarding! she is moving horizontally when she rides over a cliff that is 3.14 meters high. she lands a horizontal distance of 3.20 meters away (from the base of the cliff) How fast was she moving when she went over the edge of the cliff? [assume the laws of physics are the same even in her dreams!]

Answer 1

Let us consider the downwards direction as positive.

Gravitational acceleration = g = 9.81 m/s²

Initial velocity of the professor = V

The professor moves horizontally off the edge of the cliff.

Initial horizontal velocity of the professor = V_x = V

Initial vertical velocity of the professor = V_y = 0 m/s

Height of the cliff = H = 3.14 m

Time taken by the professor to reach the ground = T

T = 0.8 sec

Horizontal distance covered by the professor = R = 3.20 m

There is no horizontal force acting on the professor therefore the horizontal velocity of the professor is constant.

R = V_xT

3.20 = V(0.8)

V = 4 m/s

Speed of the professor when she went over the edge of the cliff = 4 m/s