Advertisements
Advertisements
प्रश्न
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.
पर्याय
t1 < t2
t1 > t2
t1 = t2
the relation between t1 and t2 depends on the mass of the particle
Advertisements
उत्तर
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.
APPEARS IN
संबंधित प्रश्न
When a carpet is beaten with a stick, dust comes out of it. Explain.
Give the magnitude and direction of the net force acting on a drop of rain falling down with a constant speed.
Fill in the following blank with suitable word :
Newton’s first law of motion is also called Galileo’s law of ………………………
State Newton’s first law of motion. Give two examples to illustrate Newton’s first law of motion.
Name the physical quantity whose unit is ‘newton’.
Find the acceleration produced by a force of 5 N acting on a mass of 10 kg.
Is it possible for a particle to describe a curved path if no force acts on it? Does your answer depend on the frame of reference chosen to view the particle?
A plumb bob is hung from the ceiling of a train compartment. If the train moves with an acceleration 'a' along a straight horizontal track , the string supporting the bob makes an angle tan−1 (a/g) with the normal to the ceiling. Suppose the train moves on an inclined straight track with uniform velocity. If the angle of incline is tan−1 (a/g), the string again makes the same angle with the normal to the ceiling. Can a person sitting inside the compartment tell by looking at the plumb line whether the train is accelerating on a horizontal straight track or moving on an incline? If yes, how? If not, then suggest a method to do so.
A force F1 acts on a particle accelerating it from rest to a velocity v. Force F1 is then replaced by F2 which decelerates the particle to rest.
A reference frame attached to the earth
(a) is an inertial frame by definition
(b) cannot be an inertial frame because the earth is revolving around the sun
(c) is an inertial frame because Newton's laws are applicable in this frame
(d) cannot be an inertial frame because the earth is rotating about its axis.
An object of mass 2 kg is sliding with a constant velocity of 4 m/s on a frictionless horizontal table. The force required to keep this object moving with the same velocity is :
How does Newton's second law of motion differ from the first law of motion?
A force of 600 dynes acts on a glass ball of mass 200 g for 12 s. If initially, the ball is at rest, find
- Final velocity
- Distance covered.
Differentiate between gravitational mass and inertial mass.
Match the following
| Column I | Column II |
| Newton’s I law | propulsion of a rocket |
| Newton’s II law | Stable equilibrium of a body |
| Newton’s III law | Law of force |
| Law of conservation of linear momentum | Flying nature of bird |
A body of mass 10 kg is acted upon by two perpendicular forces, 6 N and 8 N. The resultant acceleration of the body is ______.
- 1 m s–2 at an angle of tan−1 `(4/3)` w.r.t 6 N force.
- 0.2 m s–2 at an angle of tan−1 `(4/3)` w.r.t 6 N force.
- 1 m s–2 at an angle of tan−1 `(3/4)` w.r.t 8 N force.
- 0.2 m s–2 at an angle of tan−1 `(3/4)` w.r.t 8 N force.
Block A of weight 100 N rests on a frictionless inclined plane of slope angle 30° (figure). A flexible cord attached to A passes over a frictonless pulley and is connected to block B of weight W. Find the weight W for which the system is in equilibrium.
The masses of 10 kg and 20 kg, respectively, are connected by massless spring as shown in the figure. A force of 200 N acts on the 20 kg mass. At the instant shown, the 10 kg mass has acceleration of 12 m/s2. What is the acceleration of 20 kg mass?
(g = 10 m/s2)
What does inertia measure in an object?
An interstellar spacecraft, far away from the influence of any star or planet, is moving at high speed under the influence of fusion rockets (due to the thrust exerted by fusion rockets, the spacecraft is accelerating). Suddenly the engine malfunctions and stops. The spacecraft will ______.
