Question

A bullet is moving at a speed of 10 ms^-1 strikes a wooden plank. The bullet penetrates the plank 2 cm deep and remains embedded in it. The acceleration of the bullet is

• A. -1000 ms^-2
• B. -2500 ms^-2
• C. 1000 ms^-2
• D. 2500 ms^-2

Answer 1

The correct option is B

-2500 ms^-2

Step 1: Given data

Initial Speed of the bullet U = 10 ms^-1

The final speed of bullet V = 0 ms^-1 ( Because after penetrating for some distance the bullet finally stopped).

penetrated distance of the bullet through wooden plank X = 2 cm = 0.02 m

Step 2: Calculation of acceleration

From the Kinematic equation,

V² = U² + 2aX

Where a is the acceleration.

Substituting the given values,

0² =10² +( 2 $\times a\times 0.02$)

0 = 100 + $2\times a\times 0.02$

100 = $-$ $2\times a\times 0.02$

50= $-$0.02 (a)

a= $-$$\frac{50}{0.02}$ =$-$ 2500 ms^-2

Hence, The acceleration of the bullet is $-$2500 ms^-2. Hence option (b) is correct.