SATHEE: Motion in a Straight Line

Motion in a Straight Line - Result Question 40

41. Two bodies, A (of mass $1 k g$ ) and B (of mass $3 k g$ ), are dropped from heights of $16 m$ and $25 m$ , respectively. The ratio of the time taken by them to reach the ground is

(a) $12 / 5$

(b) $5 / 12$

(d) $5 / 4$

[2006]

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Answer:

Correct Answer: 41. (c)

Solution:

$h = \frac{1}{2} g t^{2}$ ,

For first body, $16 = \frac{1}{2} g t_{1}^{2}$

For second body, $25 = \frac{1}{2} g t_{2}^{2}$

$∴ \frac{16}{25} = \frac{t_{1}^{2}}{t_{2}^{2}} \Rightarrow \frac{t_{1}}{t_{2}} = \frac{4}{5}$ .

If a body is a dropped from some height, the motion is independent of mass of the body. The time taken to reach the ground $t = \sqrt{2 h / g}$ and final velocity $V = \sqrt{2 g h}$ and initial velocity, $u = 0$ . (a) For part $A B$

From 3rd equation of motion $v^{2} = u^{2} - 2 g H$

$0 = u^{2} - 2 g (H / 2) = u^{2} - g H$

$H = \frac{u^{2}}{g} = \frac{10^{2}}{10} = 10 m$

Motion in a Straight Line - Result Question 40

41. Two bodies, A (of mass $1 k g$ ) and B (of mass $3 k g$ ), are dropped from heights of $16 m$ and $25 m$ , respectively. The ratio of the time taken by them to reach the ground is

Answer:

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Motion in a Straight Line - Result Question 40

41. Two bodies, A (of mass 1kg ) and B (of mass 3kg ), are dropped from heights of 16m and 25m, respectively. The ratio of the time taken by them to reach the ground is

Answer:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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41. Two bodies, A (of mass $1 k g$ ) and B (of mass $3 k g$ ), are dropped from heights of $16 m$ and $25 m$ , respectively. The ratio of the time taken by them to reach the ground is