Question

You throw a rock straight up with a speed of 10 m/s. How long will it take to reach the top of its path? Neglect the effects of air resistance in this and the next question.

a. 1.02 s

b. 0.51 s

c. 1.42 s

d. 2.84 s

Answer 1

Answer 2

To calculate the time it takes for the rock to reach the top of its path, we can use the fact that the vertical motion of the rock follows a constant acceleration due to gravity (neglecting air resistance). The acceleration due to gravity is approximately 9.8 m/s², pointing downward.

When the rock reaches the top of its path, its vertical velocity will become zero before it starts falling back down. The time it takes to reach the top can be determined using the following kinematic equation:

v_f = v_i + a * t

where: v_f = final velocity (0 m/s at the top of its path) v_i = initial velocity (10 m/s, upward) a = acceleration due to gravity (-9.8 m/s², pointing downward) t = time (unknown)

We can rearrange the equation to solve for 't':

t = (v_f - v_i) / a

t = (0 - 10) / (-9.8)

t ≈ 1.02 seconds

So, the correct answer is:

a. 1.02 s