Question

Motion in One-dimension ! ​

Answer 1

Answer:

option C is the right.

Explanation:

I hope this helps you

Answer 2

Question:

From the following displacement-time graph find out the velocity of a moving body:

(A) 1/√3 m/s

(B) 3 m/s

(C) √3 m/s

(D) 1/3 m/s

Answer:

(C) √3 m/s

✯ Concept used:

Velocity = Slope of distance-time graph = tan θ

(where θ is the angle made with Y axis)

Solution:

Here, angle made with Y-axis = 90° - 30°

⇒ Angle made with Y axis = 60°

Now, we know that slope of distance-time graph gives the velocity.

So, Slope = tan θ

⇒ Slope = tan 60°

⇒ Slope = √3 m/s

∴ Velocity = √3 m/s

Solution: (Alternate method )

We know that:

Velocity = Displacement ÷ Time

Concept: (alternate)

• The side where vector makes angle θ is taken as cos θ
• The side which is perpendicular to this cos θ is taken as sin θ

Applying this vector logic,

• Displacement = cos 30°
• Time = sin 30°

So,

Velocity = Displacement ÷ Time

⇒ Velocity = cos 30° ÷ sin 30°

⇒ Velocity = cot 30°

⇒ Velocity = √3 m/s

∴ Velocity = √3 m/s