Answer:
<em>Correct choice: b 4H</em>
Explanation:
<u>Conservation of the mechanical energy</u>
The mechanical energy is the sum of the gravitational potential energy GPE (U) and the kinetic energy KE (K):
E = U + K
The GPE is calculated as:
U = mgh
And the kinetic energy is:

Where:
m = mass of the object
g = gravitational acceleration
h = height of the object
v = speed at which the object moves
When the snowball is dropped from a height H, it has zero speed and therefore zero kinetic energy, thus the mechanical energy is:

When the snowball reaches the ground, the height is zero and the GPE is also zero, thus the mechanical energy is:

Since the energy is conserved, U1=U2
![\displaystyle mgH=\frac{1}{2}mv^2 \qquad\qquad [1]](https://tex.z-dn.net/?f=%5Cdisplaystyle%20mgH%3D%5Cfrac%7B1%7D%7B2%7Dmv%5E2%20%20%20%20%5Cqquad%5Cqquad%20%5B1%5D)
For the speed to be double, we need to drop the snowball from a height H', and:

Operating:
![\displaystyle mgH'=4\frac{1}{2}m(v)^2 \qquad\qquad [2]](https://tex.z-dn.net/?f=%5Cdisplaystyle%20mgH%27%3D4%5Cfrac%7B1%7D%7B2%7Dm%28v%29%5E2%20%5Cqquad%5Cqquad%20%5B2%5D)
Dividing [2] by [1]

Simplifying:

Thus:
H' = 4H
Correct choice: b 4H
Answer:
Option C
Explanation:
According to the question:
Force exerted by the team towards south, F = 10 N
Force exerted by the opposite team towards North, F' = 17 N
Net Force, 

Thus the force will be along the direction of force whose magnitude is higher
Therefore,
towards North
Answer:
unmmmmmmmm I think the answerA
Answer:
Explanation:
E₀ = 229.1 V/m
E = E₀ / √2 = 229.1 / 1.414 = 162 V/m
B = E / c ( c is velocity of em waves )
= 162 / (3 x 10⁸) = 54 x 10⁻⁸ T
rate of energy flow = ( E x B ) / μ₀
= 162 x 54 x 10⁻⁸ / 4π x 10⁻⁷
= 69.65 W per m².
Answer:
the spring compressed is 0.1878 m
Explanation:
Given data
mass = 3 kg
spring constant k = 750 N/m
vertical distance h = 0.45
to find out
How far is the spring compressed
solution
we will apply here law of mass of conservation
i.e
gravitational potential energy loss = gain of eastic potential energy of spring
so we say m×g×h = 1/2× k × e²
so e² = 2×m×g×h / k
so
we put all value here
e² = 2×m×g×h / k
e² = 2×3×9.81×0.45 / 750
e² = 0.0353
e = 0.1878 m
so the spring compressed is 0.1878 m