# In an Imaginary Atmosphere, the Air Exerts a Small Force F on Any Particle in the Direction of the Particle'S Motion. a Particle of Mass M Projected Upward Takes Time T1 in Reaching the Maximum - Physics

MCQ

In an imaginary atmosphere, the air exerts a small force F on any particle in the direction of the particle's motion. A particle of mass m projected upward takes time t1 in reaching the maximum height and t2 in the return journey to the original point. Then.

#### Options

• t1 < t2

•  t1 > t2

• t1 = t2

• the relation between t1 and t2 depends on the mass of the particle

#### Solution

t1 > t2

Let acceleration due to air resistance force be a.
Let H be maximum height attained by the particle.
Direction of air resistance force is in the direction of motion.

In the upward direction of motion,
$a_{eff} = \left| g - a \right|$
$t_1 = \sqrt{\frac{2H}{\left| g - a \right|}} . . . (1)$
In the downward direction of motion,
$a_{eff} = g + a$
$t_2 = \sqrt{\frac{2H}{g + a}} . . . (2)$
So, t1 > t2.

Concept: Newton's First Law of Motion
Is there an error in this question or solution?

#### APPEARS IN

HC Verma Class 11, Class 12 Concepts of Physics Vol. 1
Chapter 5 Newton's Laws of Motion
MCQ | Q 12 | Page 78