Question

Difficulty: EasyKinematics and Linear Motion

A body starting from rest accelerates uniformly along a straight path at a rate of 2.5 m/s22.5\text{ m/s}^2. What is the distance covered by the body in 4.0 s4.0\text{ s}?

  1. A
    10 m10\text{ m}
  2. 20 m20\text{ m}Answer
  3. C
    40 m40\text{ m}
  4. D
    5.0 m5.0\text{ m}

Answer

The distance covered by the body in 4.0 s4.0\text{ s} is 20 m20\text{ m}.
Using the kinematic relation s=ut+12at2s = ut + \frac{1}{2}at^2 with u=0 m/su = 0\text{ m/s}, a=2.5 m/s2a = 2.5\text{ m/s}^2, and t=4.0 st = 4.0\text{ s} gives s=0+12×2.5×(4.0)2=20 ms = 0 + \frac{1}{2} \times 2.5 \times (4.0)^2 = 20\text{ m}.

Step-by-Step Solution

1
Identify the given kinematic values.
Initial velocity u=0 m/su = 0\text{ m/s}, acceleration a=2.5 m/s2a = 2.5\text{ m/s}^2, and time t=4.0 st = 4.0\text{ s}.
The problem states the body starts from rest and undergoes uniform linear acceleration.
2
Select the appropriate formula for distance under uniform acceleration.
s=ut+12at2s = ut + \frac{1}{2}at^2
This equation connects initial velocity, acceleration, elapsed time, and total displacement.
3
Substitute the given values into the equation and compute displacement.
s=(0)(4.0)+12(2.5)(4.0)2=0.5×2.5×16=20 ms = (0)(4.0) + \frac{1}{2}(2.5)(4.0)^2 = 0.5 \times 2.5 \times 16 = 20\text{ m}.
Evaluating the expressions yields the distance traveled in meters.

Key Concept

Kinematic Equation for Linear Distance Under Uniform Acceleration
Estimated Time:45s
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