Explanation

The driving force in energy transfer is the factor that causes energy to flow from one place to another.

Heat flows from higher to lower temperature.

Temperature difference drives conduction, convection, and radiation.

Explanation

The amount of energy required to raise the temperature of a body by 1°C is called Heat capacity.

It depends on the mass and material of the body.

Unit: Joule/°C.

Explanation

When two bodies A and B are moving parallel along a straight line, the relative velocity of A with respect to B is given by:

V_AB = V_A - V_B

Explanation

The scalar product (dot product) of two vectors A and B is given by:

A · B = |A| |B| cos(θ)

Maximum value occurs when cos(θ) = 1 (θ = 0°)

Let's find the angle where the scalar product is half of its maximum value:

|A| |B| cos(θ) = (1/2) |A| |B|

cos(θ) = 1/2

θ = 60°

Explanation

Given:

Initial velocity (u) = 0 m/s (starts from rest)

Final velocity (v) = 100 m/s

Time (t) = 10 s

Acceleration (a) = (v - u) / t

a = (100 m/s - 0 m/s) / 10 s

a = 100 m/s / 10 s

a = 10 m/s²

Explanation

In interference, silence zones (or nodes) occur where the path difference between two sound waves is equal to an odd multiple of λ/2.

Path difference = (2n + 1)λ/2, where n = 0, 1, 2, ...

For the simplest case, n = 0:

Path difference = λ/2

Explanation

Given:

Time (t) = 10 seconds

Initial velocity (u) = 0 (since it's free fall from rest)

Acceleration due to gravity (g) = 10 m/s² (approx.)

Distance covered (s) = ut + (1/2)gt²

Since u = 0, s = (1/2)gt²

s = (1/2) × 10 × 10²

s = 5 × 100

s = 500 m

Explanation

When a cyclist takes a turn, they bend inward so that the resultant of their weight and the centripetal force passes through the center of gravity.

Bending provides the required centripetal force for circular motion.

Without bending, the cyclist would topple outward.

Explanation

Given:

Change in momentum (Δp) = 5 kg m/s

Time interval (Δt) = 2 seconds

Force (F) is given by the formula: F = Δp / Δt

F = 5 kg m/s / 2 s

F = 2.5 N

Explanation

• Light travels from denser to rarer medium.
• Angle of incidence > Critical angle.