Arocket sled used in old air force test could accelerate a volunteer at rates of 90m/s^2. with this acceleration being constant, how long would it take for one of these rocket sleds to travel the length of a one kilometer test track if it starts from rest? a) 11.1sec b) 22.2sec c)4.71sec d) 32.2sec

option (c) 4.71 seconds

Explanation:

Given:

Distance to be covered = 1 km = 1000 m

Acceleration, a = 90 m/s²

From Newton's equation of motion

where,  

s is the distance

u is the initial speed  = 0 m/s ( since it starts from rest )

a is the acceleration

t is the time

on substituting the respective values, we get

or

45t² = 1000

or

t² = 22.22

or

t = 4.71 seconds

Hence, the correct answer is option (c) 4.71

what is the question because that is not a question.

answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.