A bullet of mass 10g is fired from a riffle with a muzzle the speed of 800m/s. After passing through a mud wall 1m thick, the speed of bullet drops to 200m/s. Calculate the work done by the mud wall on the bullet.
Answers
Answer:
Initial velocity or u=800m/s
Final velocity or v= 100m/s
Mass of the bullet given= 10g=0.01 kg
Distance covered by the bullet or S= 1m
We know that \bold{v^{2}=u^{2}+2 a S} where a is the acceleration we need to calculate.
Substituting the values, we get:
(100)^{2}=(800)^{2}+2 \times a \times 1
100×100=800×800+2a
2a= 640000-10000
a=315000 m / s^{2}
We know that F=ma
=0.01 \times 315000 m / s^{2}=3150 N
The resistance that the mud wall offers is equal to the force =3150N
We can also calculate the resistance using the formula for kinetic energy as the resistance would be equal to the difference between the initial kinetic energy and the final kinetic energy.
-R=\frac{1}{2}\left(v^{2}\right)-\frac{1}{2}\left(u^{2}\right) We use –R because resistance is always negative)
\bold{-R=\frac{1}{2}\left(v^{2}-u^{2}\right)}
-R= -½ (630000)x
Explanation:
another way
1
Secondary School Physics 5 points
A bullet weighing 10g is fired with a velocity of 800m/s . after passing through a mud wall 1m thick its velocity decreases to 100 m/s .find the resistance offered by the mud wall.
Ask for details Follow Report by Raghwendrarsk75 26.09.2017
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nehasikarwar42 Ambitious
a = u^2-v^2/ 2s
a = 800^2 - 100^2/2×1
a =315000 m/s^2
Now, F = ma
F = 10 ×1/1000×315000
F = 3150N