When you push a door closed it doesn't travel in a straight line it turns around the hinges this is an example of a line
Answer:

Explanation:
Given,
Number of turns, N = 645 N
Area, A = 20.25 m²
Earth Magnetic field, B = 5 x 10⁻⁵ T
Maximum Emf = 1.25 V.
Angular velocity, ω = ?
Using Induced Emf formula




Angular velocity of the coil = 
Answer:
640 J
640 J
Explanation:
ΔKE = ½ mv² − ½ mu²
ΔKE = ½ m (v² − u²)
ΔKE = ½ (80 kg) ((5 m/s)² − (3 m/s)²)
ΔKE = 640 J
Work = ΔE
Work = 640 J
Answer:
a)
, b) 
Explanation:
a) The acceleration due to gravity inside the planet is:





b) The acceleration at the surface of the planet is:

All of these things were seen in formal experiments by the 19th century. But some of them are easy to see in your own home. It's obvious that light can reflect - you just have to look in a mirror. Light bounces off the mirror and goes into your eye so you can see yourself. It's also obvious that light can refract: All you have to do is put a spoon in a large glass of water and watch how the spoon appears to bend.
That happens because the light is bending as it moves between air and water. Both of these things can be seen even more clearly in a laboratory using beams of light or lasers.