Physical development , Cognitive Development , psychosocial development I think!
1,000 W = 1 kW
100 W = 0.1 kW
(0.1 kW) x (6 h) = 0.6 kWh <=== energy
(0.6 kWh) x (£0.1359/kWh) = £0.0815 <=== cost of it
Answer:
(a)
(b)
(c) K.E. = 21.168 J
(d)
Explanation:
Given:
- mass of a block, M = 3.6 kg
- initial velocity of the block,
- constant downward acceleration,
That a constant upward acceleration of is applied in the presence of gravity.
∴
- height through which the block falls, d = 4.2 m
(a)
Force by the cord on the block,
∴Work by the cord on the block,
We take -ve sign because the direction of force and the displacement are opposite to each other.
(b)
Force on the block due to gravity:
∵the gravity is naturally a constant and we cannot change it
∴Work by the gravity on the block,
(c)
Kinetic energy of the block will be equal to the net work done i.e. sum of the two works.
mathematically:
K.E. = 21.168 J
(d)
From the equation of motion:
putting the respective values:
is the speed when the block has fallen 4.2 meters.
Answer:
Force,
Explanation:
There are two positive charges, 2 C and 5 C, separated by a distance of 20 cm in a vacuum. What is the value of the modulus of the electrostatic force between them?
We have,
Charge on object 1, q₁ = 2 C
Charge on object 2, q₂ = 5 C
Distance between charges, r = 20 cm = 0.02 m
The electric force between two charges is given by the formula as follows :
Plugging all the values we get :
So, the electric force between two charges is .