Answer:
a. 8p
Explanation:
We are given that
Radius of hollow sphere , R1=R
Density of hollow sphere=![\rho](https://tex.z-dn.net/?f=%5Crho)
After compress
Radius of hollow sphere, R2=R/2
We have to find density of the compressed sphere.
We know that
![Density=\frac{mass}{volume}](https://tex.z-dn.net/?f=Density%3D%5Cfrac%7Bmass%7D%7Bvolume%7D)
![Mass=Density\times volume=Constant](https://tex.z-dn.net/?f=Mass%3DDensity%5Ctimes%20volume%3DConstant)
Therefore,![\rho_1 V_1=\rho_2V_2](https://tex.z-dn.net/?f=%5Crho_1%20V_1%3D%5Crho_2V_2)
Volume of sphere=![\frac{4}{3}\pi r^3](https://tex.z-dn.net/?f=%5Cfrac%7B4%7D%7B3%7D%5Cpi%20r%5E3)
Using the formula
![\rho\times \frac{4}{3}\pi R^3=\rho_2\times \frac{4}{3}\pi (R/2)^3](https://tex.z-dn.net/?f=%5Crho%5Ctimes%20%5Cfrac%7B4%7D%7B3%7D%5Cpi%20R%5E3%3D%5Crho_2%5Ctimes%20%5Cfrac%7B4%7D%7B3%7D%5Cpi%20%28R%2F2%29%5E3)
![\rho R^3=\rho_2\times \frac{R^3}{8}](https://tex.z-dn.net/?f=%5Crho%20R%5E3%3D%5Crho_2%5Ctimes%20%5Cfrac%7BR%5E3%7D%7B8%7D)
![\rho_2=8\rho](https://tex.z-dn.net/?f=%5Crho_2%3D8%5Crho)
Hence, the density of the compressed sphere=![8\rho](https://tex.z-dn.net/?f=8%5Crho)
Option a is correct.
Answer:
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Explanation:dfbgdhzfgbfxgzbfxd
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The car will move in a speed of 45 meter per second
Answer:
4.17 m/s²
Explanation:
We are told the reaction time is 0.2 s. Now, during this reaction time the car is going to travel an additional distance of
: x = u × t = 40 × 0.2 = 8 m
where u is the initial velocity of the car which is 40.0 m/s.
We are told that he had 200 m to stop before applying brakes. Thus, after applying brakes, he now has a distance to cover of; s = 200 - 8 = 192 m
Since vehicle is coming to rest acceleration would be negative, thus using Newton's equation of motion, we have;
v
² = u² - 2as
v = 0 m/s since it's coming to rest
u = 40 m/s
s = 192 m
Thus;
0² = 40² - 2(a)(192)
0² = 1600 - 384a
a = 1600/384
a = 4.17 m/s²