Question

A body moving on straight line such that at t = 0, u = 5 m/s and acceleration a = -1 m/s, speed at t=10 s is (A)-5 m/s (B) 5 m/s (C) 10 m/s (D) -10 m/s​

Answer 1

Answer:

Ans - 5m/s

Explanation:

u=5

a=-1

t=10

V=u+at

=5-1*10

= -5m/s

Answer 2

Concept:

• One dimensional motion
• Kinematics equation

Given:

• The initial velocity u = 5 m/s
• The acceleration a = -1 m/s^2
• The duration of time t = 10 s

Find:

• The final speed at t = 10 s

Solution:

We know the kinematics equation

v = u+ at

u = 5 m/s, a = -1 m/s^2, t = 10 s

v = 5 + (-1) (10)

v = 5-10

v = -5 m/s

-5 m/s is the velocity of the body.

Velocity is a vector quantity, so it has direction in addition to magnitude.

The question has asked for speed which is a scalar quantity and only has magnitude.

The speed is just 5 m/s

The speed at t = 10 s is 5 m/s.

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