Answer:
The mass density of the string is (0.3/L)kg/m
Explanation:
Mass density of the string = Mass/Length
Mass = 0.3kg
The length of the string is unknown so it is assumed to be L meter(s)
Therefore, mass deny of the string = 0.3kg/Lm = (0.3/L)kg/m
Answer:
It is 3 m/s² downward.
Explanation:
The mass of an object, m = 30 kg
Upward force, F = 200 N
Downward force, F' = -300 N
We need to find the magnitude and direction of its acceleration.
Net force = F+F'
= 200+(-300)
= -100 N
We know that,
Force, F = ma, a is acceleration of the object

Hence, the acceleration is -3 m/s² and it is acting in the downward direction.
Explanation:
The given data is as follows.
Mass, m = 75 g
Velocity, v = 600 m/s
As no external force is acting on the system in the horizontal line of motion. So, the equation will be as follows.
where,
= mass of the projectile
= mass of block
v = velocity after the impact
Now, putting the given values into the above formula as follows.
![75(10^{-3}) \times 600 = [(75 \times 10^{-3}) + 50] \times v](https://tex.z-dn.net/?f=75%2810%5E%7B-3%7D%29%20%5Ctimes%20600%20%3D%20%5B%2875%20%5Ctimes%2010%5E%7B-3%7D%29%20%2B%2050%5D%20%5Ctimes%20v)
= 
v = 0.898 m/s
Now, equation for energy is as follows.
E = 
= 
= 13500 J
Now, energy after the impact will be as follows.
E' = ^{2}](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B2%7D%5B75%20%5Ctimes%2010%5E%7B-3%7D%20%2B%2050%5D%280.9%29%5E%7B2%7D)
= 20.19 J
Therefore, energy lost will be calculated as follows.
= E E'
= (13500 - 20) J
= 13480 J
And, n = 
= 
= 99.85
= 99.9%
Thus, we can conclude that percentage n of the original system energy E is 99.9%.
Answer:
Explanation:
T = 2π√(L/g)
If you increase L to 2L, the period is increased by a factor of √2
T = 3.5√2 ≈ 4.9 s