I'm pretty sure its D. Both B. and C.
Answer:
748.8 kJ
Explanation:
Kinetic energy is given by
where m is the mass of the body, v is the velocity
Substituting 2600 Kg for m and 24 m/s for velocity
Therefore, kinetic energy is 748.8 kJ
The net force that is applied to the passenger during the elevator acceleration is 218.75 N.
<h3>What is net force?</h3>
This is the single force obtained from the combinatiion of two or more forces
To calculate the net force that is applied to the passenger during the elevator's acceleration, we use the formula below.
Formula:
- F = m(v-u)/t............ Equation 1
Where:
- F = force
- m = mass
- v = Final velocity
- u = initial velocity
- t = time.
From the question,
Given:
- m = 70 kg
- u = 0 m/s
- v = 12.5 m/s
- t = 4 s
Substitute these values into equation 1
Hence, The net force that is applied to the passenger during the elevator acceleration is 218.75 N.
Learn more about net force here: brainly.com/question/13370981
The efficiency can never be 100 because some of the work will be transferred into thermal energy. In turn, causing the percentage to decrease. This is basically the second law of thermodynamics.
Answer:
Same as before.
Explanation:
we can use momentum conservation to solve the problem.
Let mass of child be m and of the sled be M. Also let both have initial velocity u.
since, child fells off on the sled it will still have same velocity of ''u''.
By momentum conservation we have,
(M + m) x u = m x u + M x v
⇒ Mu=Mv
⇒ u=v
Hence, velocity of the sled remains the same.