Given Data:

• Work done (W) = 60 J
• Time taken (t) = 6 seconds

Formula for Power: P=WtP=tW

Calculations: P=60 J6 sP=6s60J

Result:

• Power (P) = 10 watts (W)

Explanation:

• Power is the rate at which work is done or energy is transferred per unit of time.
• In this case, the power exerted by the man is 10 watts, which means he is exerting energy at a rate of 10 joules per second.

i) Motion of a Car around a Curve:

• The kind of motion exhibited by a car moving with constant speed turning around a curve is uniform circular motion.
• In this motion, the car maintains a constant speed while continuously changing its direction due to the curve, resulting in a circular path.

ii) Motion of an Electron Orbiting around a Nucleus:

• The kind of motion displayed by an electron orbiting around a nucleus is uniform circular motion.
• In an atom, electrons revolve around the nucleus in circular paths at a constant speed, maintaining a stable orbit.

Answer to Question (b):

Given:

• Radius of circular orbit, r=36,000r=36,000 km
• Time taken to revolve around the Earth, T=24T=24 hours

To Calculate:

• Speed of the artificial satellite in its orbit.

Solution:

1. Convert the time from hours to seconds since speed is measured in meters per second.

   • 2424 hours ×60×60 minutes/hour ×60×60 seconds/minute = 86,40086,400 seconds.

2. Apply the formula for the speed of an object in circular motion:

   • Speed v=2πrTv=T2πr

3. Substitute the given values into the formula:

   • Speed v = \frac{2 \pi \times 36,000 km}{86,400 ) seconds }
   • Speed v=72,000π86,400v=86,40072,000π km/s
   • Speed v=20π24v=2420π km/s
   • Speed v=5π6v=65π km/s
   • Speed v≈2.62v≈2.62 km/s (approximately)

Result:

• The speed of the artificial satellite in its circular orbit around the Earth is approximately 2.622.62 km/s.