6) The temperature of 10 kg of a substance rises by 55°C when heated. Calculate the
1 answer:
You might be interested in
Answer: catching the ball is a better choice.
Explanation:
The collision of 2 objects involves involves large impact force since the force is inversely proportional to the time in which the momentum of the object changes.
Mathematically
If we catch the ball we increase the time in which the momentum of the ball is decreased thus the impact force that acts on us is lower as larger time is allowed for the ball to decrease it's momentum.
If we allow the ball to hit us the momentum of the ball changes in a short period of time thus applying a large impact force on our body thus increasing the chances of toppling.
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
For the speed to be double, we need to drop the snowball from a height H', and:
Operating:
Dividing [2] by [1]
Simplifying:
Thus:
H' = 4H
Correct choice: b 4H