Answer: Option (c) is the correct answer.
Explanation:
When the child is tossed up into the air then she gains kinetic energy as the child has moved from its initial position.
It is given that mass is 20 kg, velocity is 
, and height is 2 m.
Calculate the kinetic energy of child as follows.
kinetic energy = 
= 
= 
= 
Also, when child falls off the ground then she will have gravitational potential energy.
Calculate gravitational potential energy of child as follows.
Potential energy = m × g × h
= 
= 
When you heat something of cool it down you don't change the substance you might change the why is looks, but it is still the same substance. For example you cool water to 0 degrees Celsius it turns into ice but it still is two parts hydrogen and one part oxygen H2O. Physical changes will change state and/or form but it will still be what it originally was on the molecular level. Hope that helped.
<span>Force = Work done / distance = 4Nm / 2m = 2N</span>
Answer:
(a) = 3.7 × 10⁻⁵
(b) = 4.1 × 10⁻⁶ N.M²/C
Explanation:
(a) Diameter of the sphere, d = 1.2 m
Radius of the sphere, r = 0.6 m
Surface charge density, = 8.1 mC/m2 = 8.1 × 10⁻⁶ C/m²
Total charge on the surface of the sphere,
Q = Charge density × Surface area
= 4πr²σ
= 4 (3.14) (0.12²) (8.1 × 10⁻⁶)
= 3.66 × 10⁻⁵C
≅ 3.7 × 10⁻⁵C
Therefore, the net charge on the sphere is 3.7 × 10⁻⁵C
(b)
Total electric flux (∅)
=Q / ε₀
ε₀ = 8.854 × 10⁻¹² N⁻¹C² m⁻²
Q = 3.66 × 10⁻⁵C
= 3.66 × 10⁻⁵ / 8.854 × 10⁻¹²
= 4.1 × 10⁻⁶ N.M²/C
