Question

an objest of mass 20 g lift up to a height of 200 cm for 10 sec what will be power in this case if g is 10m/s2 also clculate energy if same object is start moving with a speed of 10 m per second​

Answer 1

Given:-

• Mass ,m = 20 g = 20/1000 = 0.02KG

• height ,h = 200cm = 200/100= 2m

• Time ,t = 10s

• Acceleration due to gravity ,g = 10m/s²

• velocity ,v = 10m/s

To Find:-

• Power ,P

• Energy

Solution:-

As we know that Power is defined as the rate of doing work .

• P = W/t

Substitute the value we get

→ P = mgh/t

→ P = 0.02×10×2/2

→ P = 0.4/2

→ P = 0.2

Therefore, the power of object is 0.2 watt.

Now , calculating the Energy

• K.E = 1/2mv²

Substitute the value we get

→ K.E = 1/2×0.02×10²

→ K.E = 1/2×0.02×100

→ K.E = 1/2×2

→ K.E = 1 Joule

Therefore, the energy of the object is 1 Joule.