SATHEE: Laws of Motion - Result Question 25

Laws of Motion - Result Question 25

25. Three blocks with masses $m, 2 m$ and $3 m$ are connected by strings as shown in the figure. After an upward force F is applied on block $m$ , the masses move upward at constant speed $v$ . What is the net force on the block of mass $2 m$ ? ( $g$ is the acceleration due to gravity)

[2013]

(a) $2 m g$

(b) $3 m g$

(d) zero

Show Answer

Answer:

Correct Answer: 25. (d)

Solution:

From figure

$F = 6 m g$ ,

As speed is constant, acceleration $a = 0$

$∴ 6 m g = 6 m a = 0, F = 6 m g$

$∴ T = 5 m g, T^{'} = 3 m g$

$T^{''} = 0$

$F_{net}$ on block of mass $2 m$

$= T - T^{'} - 2 m g = 0$

As all blocks are moving with constant speed, then acceleration is zero, so force is zero.

$∵ v =$ constant

so, $a = 0$ , Hence, $F_{net} = m a = 0$

Play Store

App Store

Ask SATHEE

Welcome to SATHEE !
Select from 'Menu' to explore our services, or ask SATHEE to get started. Let's embark on this journey of growth together! 🌐📚🚀🎓

I'm relatively new and can sometimes make mistakes.
If you notice any error, such as an incorrect solution, please use the thumbs down icon to aid my learning.
To begin your journey now, click on "I understand".

Laws of Motion - Result Question 25

25. Three blocks with masses m,2m and 3m are connected by strings as shown in the figure. After an upward force F is applied on block m, the masses move upward at constant speed v. What is the net force on the block of mass 2m ? ( g is the acceleration due to gravity)

Answer:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

Menu

25. Three blocks with masses $m, 2 m$ and $3 m$ are connected by strings as shown in the figure. After an upward force F is applied on block $m$ , the masses move upward at constant speed $v$ . What is the net force on the block of mass $2 m$ ? ( $g$ is the acceleration due to gravity)