The correct option is (A) <span>the first law of thermodynamics
Explanation:
The first law of thermodynamics takes the idea of law of conservation of energy and modify it for thermodynamics systems. It is the total internal energy of the systems equals to the amount of heat added "to" the system and the workdone "by" the system given as:
</span>ΔU = Q - W
<span>Q = heat added TO the system
W = work BY the system
</span>ΔU = Total internal energy
<span>
But the total internal energy is CONSERVED; it means that energy cannot be created or destroyed; it can only be transformed from one form to another. Hence the correct option is (A).</span>
The strong magnetic fields is Long rang attractive power Reuther then week magnetic field.
Answer:
Acceleration of that planet is 30
.
Given:
initial speed of hammer = 0 
time = 1 s
distance = 15 m
To find:
Acceleration due to gravity = ?
Formula used:
Distance covered by hammer is given by,
s = ut + 
s = distance
u = initial speed of hammer
t = time taken by hammer to reach ground
a = acceleration
Solution:
Distance covered by hammer is given by,
s = ut + 
s = distance
u = initial speed of hammer
t = time taken by hammer to reach ground
a = acceleration
u = 0
t = 1 s
s = 15 m
a = g
Thus substituting these value in above equation.
15 = 0 + 
g = 15 × 2
g = 30 
Thus, acceleration of that planet is 30
.
when the ball hits the floor and bounces back the momentum of the ball changes.
the rate of change of momentum is the force exerted by the floor on it.
the equation for the force exerted is
f = rate of change of momentum

v is the final velocity which is - 3.85 m/s
u is initial velocity - 4.23 m/s
m = 0.622 kg
time is the impact time of the ball in contact with the floor - 0.0266 s
substituting the values

since the ball is going down, we take that as negative and ball going upwards as positive.
f = 189 N
the force exerted from the floor is 189 N
Ocean currents are formed by a type of heat transfer that is convection