Answer:
185.25 m/s
Explanation:
consider the motion of the combination of bullet and block after the collision
v₀ = initial speed just after the collision
v' = final speed = 0 m/s
μ = Coefficient of friction = 0.6
g = acceleration due to gravity = 9.8 m/s²
a = acceleration of the combination = - μ g = - (0.6) (9.8) = - 5.88 m/s²
d = stopping distance = 13 m
using the kinematics equation
v'² = v₀² + 2 a d
0² = v₀² + 2 (- 5.88) (13)
v₀ = 12.4 m/s
m = mass of the bullet = 9.9 g = 0.0099 kg
M = mass of the wood = 138 g = 0.138 kg
v = speed of bullet before collision
v₀ = speed of combination after the collision = 12.4 m/s
Using conservation of momentum
m v = (m + M) v₀
(0.0099) v = (0.0099 + 0.138) (12.4)
v = 185.25 m/s
Answer:
Explanation:
Given
Launch angle =u
Initial Speed is 
Horizontal acceleration is 
At maximum height velocity is zero therefore



Total time of flight 
During this time horizontal range is


For maximum range 

![\frac{\mathrm{d} R}{\mathrm{d} u}=\frac{2v_0^2}{g}\left [ \cos 2u-\frac{a}{g}\sin 2u\right ]=0](https://tex.z-dn.net/?f=%5Cfrac%7B%5Cmathrm%7Bd%7D%20R%7D%7B%5Cmathrm%7Bd%7D%20u%7D%3D%5Cfrac%7B2v_0%5E2%7D%7Bg%7D%5Cleft%20%5B%20%5Ccos%202u-%5Cfrac%7Ba%7D%7Bg%7D%5Csin%202u%5Cright%20%5D%3D0)


(b)If a =10% g

thus 

The plane is not accelerating.
Hope this helps!
It is true that only half of the moon is always illuminated
by the sun. The reason why the moon
changes it phases is because Moon orbits around the Earth, and due to this some
areas of the half of the moon will not be lit by the sun.