Explanation

Velocity is a vector quantity. 

A vector quantity has both magnitude and direction.

Velocity, which describes the rate of change of position in a specific direction, needs both a magnitude (speed) and a direction to be fully defined. 

Vector Quantities: Velocity, momentum, torque, acceleration.

Scalar Quantities: Work, distance, speed, mass.

Explanation

Hazrat Ismael (AS) is called Abu-ul-Arab (Father of the Arabs) because Arab tribes trace their lineage through him.

He settled in Makkah and married into the Jurhum tribe, giving rise to Arab ancestry.

Explanation

In simple harmonic motion (SHM), the restoring force is given by:

F = -kx

Where:  

- F is the restoring force  

- k is the spring constant  

- x is the displacement from the equilibrium position  

The restoring force is minimum when displacement x = 0, i.e., at the equilibrium position.

Explanation

Change in momentum = 20 − 5 = 15 kg·m/s

Time = 3 s → Force = 15 / 3 = 5 N

Explanation

Pair production occurs when a high-energy γ-ray photon is converted into an electron and a positron near a nucleus.

It is a quantum phenomenon that requires photon energy greater than 1.022 MeV.

Explanation

Force is defined as the rate of change of linear momentum with respect to time.

According to Newton’s second law, force causes a change in an object’s momentum.

Explanation

Commutative property means the order doesn’t matter: 𝐴 ∗ 𝐵 = 𝐵 ∗ 𝐴.

Union ∪ is commutative, so 𝐴 ∪ 𝐵 = 𝐵 ∪ 𝐴.

Explanation

Spring potential energy is given by U = 1/2kx².

If stretching to distance S gives 10 J, then to stretch to 2S, the energy becomes 1/2k(2S)² = 4×10 = 40 J.

So, additional work =  40−10 = 30 J.

Explanation

"1st Ashra of Ramadan is "Days of mercy" (Rehmat).

2nd Ashra of Ramadan is "Days of forgiveness" (Maghfirayat).

3rd Ashra of Ramadan is "Days of refuge from hell fire" (Jahanum ke aag sa nijahat).

Explanation

The sentence is in passive voice (future tense) — "will be written".

Its active voice is: "The teacher will write a letter."