Question

A body moving along a straight line at 20 m/s decelerates at the rate of 4 m/s^2.After 2 seconds its

speed will be equal to"
A) 12 m/s
B) 16 m/s
C) 18 m/s
D) 24 m/s

Answer 1

The final velocity of a body initially moving at 20 m/s and decelerating at 4 m/s² after 2 seconds is 12 m/s.

Step-by-step explanation:

The question asks about the final velocity of a body that is moving at a constant initial velocity and then experiences deceleration (negative acceleration) over a period of time. To find the final velocity of this body after 2 seconds, we can use the kinematic equation:

v = u + at

where:
v is the final velocity (what we are trying to find),
u is the initial velocity (20 m/s),
a is the acceleration (-4 m/s², negative because it is deceleration),
t is the time (2 seconds).

Plugging in the values we get:

v = 20 m/s + (-4 m/s²)(2 s)

v = 20 m/s - 8 m/s

v = 12 m/s

The final velocity of the body after 2 seconds is 12 m/s.