A car starts from rest and accelerates at 5 m/s². At t = 4 s, a ball is dropped out of a window by a person sitting in the car. What is the velocity and acceleration of the ball at t = 6 s ? (Take g = 10 m/s² ) &lt;!-- [if !supportLineBreakNewLine]--&gt; &lt;!--[endif]--&gt;

20 m/s, 5 m/s²

20 m/s, 0

20√2 m/s, 0

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Physics Laws of Motion Physics Class 11th Laws of Motion

A car starts from rest and accelerates at 5 m/s². At t = 4 s, a ball is dropped out of a window by a person sitting in the car. What is the velocity and acceleration of the ball at
t = 6 s ? (Take g = 10 m/s² )

Option 1 -

20 m/s, 5 m/s²

Option 2 -

20 m/s, 0

Option 3 -

20√2 m/s, 0

Option 4 -

20√2 m/s, 10 m/s²

2 Views | Posted 3 weeks ago

Asked by Shiksha User

1 Answer

Answered by

alok kumar singh | Contributor-Level 10

3 weeks ago

Correct Option - 4

Detailed Solution:

velocity of car at t = 4sec is
v = u + at
v = 0 + 5 (4)
= 20 m/s
At t = 6sec
acceleration is due to gravity ∴ a = g = 10 m/s
v? = 20 m/s (due to car)
v? = u + at
= 0 + g (2) (downward)
= 20 m/s (downward)
v = √ (v? ² + v? ²)
= √ (20² + 20²)
= 20√2 m/s

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