It rises because hot air is less dense than cool air.
Answer:
4.7 x 10³ rad / s
Explanation:
During the time light goes and comes back , one slot is replaced by next slot while rotating before the light source
Time taken by light to travel a distance of 2 x 500 m is
= (2 x 500) / 3 x 10⁸
= 3.333 x 10⁻⁶ s .
In this time period, two consecutive slots come before the source of light one after another by rotation. There are 400 slots so time taken to make one rotation
= 3.333 x 10⁻⁶ x 400
= 13.33 x 10⁻⁴ s
This is the time period so
T = 13.33 X 10⁻⁴
Angular speed
= 2π / T
= 
4.7 x 10³ rad / s
Answer:
W = 68.6 N
Explanation:
Given that,
Force acting on a right side = 30 N
Mass of the object, m = 7 kg
The force of friction acting on the car = 3 N
We need to find the weight of the object.
The weight of an object is given by :
W = mg
Substitute all the values,
W = 7 × 9.8
W = 68.6 N
So, the weight of the object is 68.6 N.
The old style (incandescent) light bulb converts more energy
into heat than it does into light. If you're using it mainly as a
source of light, then it's a bummer, and its efficiency is very low.
BUT ... if you're using an incandescent light bulb as a heater, then
its efficiency is much better. It all depends on your point of view.