Question

A bridge that was 5.0 m long has been washed out by the rain several days ago. How fast must a car be going to successfully jump the stream? Although the road is level on both sides of the bridge, the road on the far side is 2.0 m lower than the road on this side.

Answer 1

Answer:

The speed of the car is 7.84 m/s

Solution:

As per the question:

Length of the bridge, l = 5.0 m

Distance, d = 2 m

Now,

Time taken by the car to reach 2 m lower is given by the kinematic eqn:

$d = ut + \frac{1}{2}at^{2}$

where

u = initial velocity = 0 m/s

t = time taken

a = g = $9.8\ m/s^{}$

Now,

$2 = 0.t + \frac{1}{2}\times 9.8\times t^{2}$

$t = 0.638\ s$

Now, we kow that the car will cover the distance equal to the length of the bridge, i.e., 5 m

Speed of the car is given by:

$v = \frac{distance\ covered}{time\ taken}$

$v = \frac{5.0}{0.638} = 7.84\ m/s$