Question

You board a stationary elevator on the ground floor. A uniform vertical gravitational field g = −9.8m/s2 is present. Before the elevator starts moving, you drop a ball from a height of 2 m above the floor.

a) How long does it take for the ball to reach the floor of the elevator?

b) How long does it take for the ball to travel from the floor to its maximum height above the floor (at which point you catch it again)?

Now the elevator starts to accelerate until it reaches a velocity of v0 = 0.5m/s just before it reaches the second floor. At this point the velocity remains constant at 0.5 m/s. As it passes the second floor you again drop the ball from a height of 2 m above the floor.

c) How long does it take the ball to hit the floor of the elevator? Hint: you might want to express the height of the elevator floor and the ball, with respect to the second floor, as a function of time. After you’ve caught the ball, and just as the elevator passes the fourth floor, it starts to accelerate again, with an acceleration give by a = +kt^2 with k = 4m/s^4 . At this point you again drop the ball from a height of 2 m above the floor.

d) How long does it take the ball to hit the floor of the elevator?

Answer 1