Question

1)the car's engine power is 44000W. Explain this number in a physical sense

Answer 1

Answer:

1) It expresses the rate (top speed) at which it can move with time.

2) P = 20 W

3) h = 18 km

Explanation:

1) Power is the rate of transfer of energy.

⇒ Power = $\frac{Energy(or workdone)}{Time}$

i.e P = $\frac{E}{t}$

Thus a car's engine power is 44000W implies that the engine of the car can propel the car at this rate. This expresses the rate (top speed) at which it can move with time.

2) m = 400g = 0.4 kg

    t = 20 s

h = 100m

g = 10 m/$s^{2}$

P = $\frac{mgh}{t}$

  = $\frac{0.4*10*100}{20}$

  = $\frac{400}{20}$

P = 20 W

3) u = 600 m/s

   g = 10 m/$s^{2}$

From the third equation of free fall,

$V^{2}$ = $U^{2}$ - 2gh

V is the final velocity, U is the initial velocity, h is the height.

0 = $(600)^{2}$ - 2 x 10 x h

0 = 360000 - 20h

20h = 360000

h = $\frac{360000}{20}$

  = 18000

h = 18 km

The maximum height of the bullet would be 18 km.