SATHEE: Kinematics Question 320

Kinematics Question 320

Question: Two cars are moving in the same direction with the same speed 30 km/hr. They are separated by a distance of 5 km, the speed of a car moving in the opposite direction if it meets these two cars at an interval of 4 minutes, will be

Options:

A) 40 km/hr

B) 45 km/hr

C) 30 km/hr

D) 15 km/hr

Show Answer

Answer:

Correct Answer: B

Solution:

The two car (say A and B) are moving with same velocity, the relative velocity of one (say B) with respect to the other $A, {\vec{v}}_{B A} = {\vec{v}}_{B} - {\vec{v}}_{A} = v - v = 0$

So the relative separation between them (= 5 km) always remains the same.

Now if the velocity of car (say C) moving in opposite direction to A and B, it’s ${\vec{v}}_{C}$ relative to ground then the velocity of car C relative to A and B will be ${\vec{v}}_{r e l .} = {\vec{v}}_{C} - \vec{v}$ But as $\vec{v}$ it’s opposite to vC

So $v_{r e l} = v_{c} - (- 30) = (v_{C} + 30) k m / h r .$

So, the time taken by it to cross the cars A and B $t = \frac{d}{v_{r e l}} \Rightarrow \frac{4}{60} = \frac{5}{v_{C} + 30}$
$\Rightarrow v_{C} = 45 k m / h r .$

Kinematics Question 320

Question: Two cars are moving in the same direction with the same speed 30 km/hr. They are separated by a distance of 5 km, the speed of a car moving in the opposite direction if it meets these two cars at an interval of 4 minutes, will be

Options:

Answer:

Solution:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

Kinematics Question 320

Question: Two cars are moving in the same direction with the same speed 30 km/hr. They are separated by a distance of 5 km, the speed of a car moving in the opposite direction if it meets these two cars at an interval of 4 minutes, will be

Options:

Answer:

Solution:

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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