To solve this exercise, it is necessary to apply the concepts of conservation of the moment especially in objects that experience an inelastic colposition.

They are expressed as,

$m_1v_1+m_2v_2 = (m_1+m_2)v_f$

Where,

$m_1$ = mass of the skier

$m_2$ = mass of the cat

$v_1$ = initial velocity of skier

$v_2$ = initial velocity of cat

$v_f$ = final velocity of both

Re-arrange to find V_f we have,

$V_f = \frac{m_1v_1+m_2v_2}{(m_1+m_2)}$

$V_f = \frac{(60)(15)+(5)(-3.8)}{(60+5)}$

$V_f = 13.55m/s$

Once the final velocity is found it is possible to calculate the change in kinetic energy, so

$\Delta KE = KE_i-KE_f$

$\Delta KE = \frac{1}{2}(m_1v_1^2+m_2v^2_2)-\frac{1}{2}(m_1+m_2)v_f^2$

$\Delta KE = \frac{1}{2}((60)(15)^2+(5)(-3.8)^2)-\frac{1}{2}(60+5)(13.55)^2$

$\Delta KE = 819.1J$

Therefore the amount of kinetic energy converted in to internal energy is 819J

3 0

3 years ago

When a tuning fork vibrates over an open pipe and the air in the pipe starts to vibrate, the vibrations in the tube are caused b

defon

Answer:

correct option is A. Resonance

Explanation:

solution

vibrations in the tube are caused by the Resonance because Resonance cause of sounds production in the musical instrument

As if resonance ( hollow cylindrical tube) immerse in cylinder of water and force in to vibration by tuning fork

As tines of tuning fork vibrate at natural frequency and it create sound wave that impinged up on opening of resonance tube

so correct option is A. Resonance

8 0

3 years ago

A crane motor exerts 3,500 W to lift a load up 5 floors in 25 seconds. How much work did the crane do?

jok3333 [9.3K]

Answer: 87500J

Explanation:

Given that,

Power exerted by crane = 3,500 W

Time taken = 25 seconds

work done by crane = ?

Since power is the rate of work done per unit time, then power is workdone by the crane divided by the time taken.

i.e power = work / time

3,500 W = work / 25 seconds

Work = 3500W x 25 seconds

Work = 87500J

Thus, 87500 joules of work was done by the crane.

4 0

3 years ago