in passing theough a wooden block 8cm thick the velocity of a beullet reduces from 700m/s to 300 m/s if the mass of the bullet is 10g find the average resitance to penetrate ?

How is some

In passing through a wooden block 8cm thick the velocity of a bullet reduces from 700m/s to 300m/s. If the average to resistance to the penetrate

To find the average resistance to penetrate the wooden block, we need to calculate the deceleration experienced by the bullet as it passes through the block.

First, let's convert the mass of the bullet from grams to kilograms:

Mass of the bullet = 10 g = 10/1000 kg = 0.01 kg

We can use the equation of motion to find the deceleration of the bullet:

v² = u² + 2as

where:
v = final velocity = 300 m/s
u = initial velocity = 700 m/s
a = acceleration (deceleration in this case)
s = distance travelled through the wooden block = 8 cm = 8/100 = 0.08 m

Rearranging the equation, we get:

a = (v² - u²) / (2s)

a = (300² - 700²) / (2 * 0.08)

Now, we can calculate the acceleration:

a = (-280,000) / 0.16
a = -1,750,000 m/s²

The negative sign indicates deceleration.

Now, to find the average resistance to penetrate, we can use Newton's second law of motion:

Force = Mass × Acceleration

We know the mass of the bullet is 0.01 kg, and the deceleration is -1,750,000 m/s².

Therefore, the average resistance to penetrate the wooden block is:

Force = 0.01 kg × (-1,750,000 m/s²)

Now, we can calculate the average resistance:

Force = -17,500 N

The average resistance to penetrate the wooden block is -17,500 Newtons (N).

change in momentum = .001 (300 - 700)

time in block = .08/(average speed
= .08 / [(700+300)/2]

Force = change in momentum/time in block