Advertisements
Advertisements
प्रश्न
A body of mass 2 kg travels according to the law x(t) = pt + qt2 + rt3 where p = 3 ms−1, q = 4 ms−2 and r = 5 ms−3. The force acting on the body at t = 2 seconds is ______.
पर्याय
136 N
134 N
158 N
68 N
Advertisements
उत्तर
A body of mass 2 kg travels according to the law x(t) = pt + qt2 + rt3 where p = 3 ms−1, q = 4 ms−2 and r = 5 ms−3. The force acting on the body at t = 2 seconds is 136 N.
Explanation:
Given, mass = 2 kg
`x(t) = pt + qt^2 + rt^3`
`v = (dx)/(dt) = p + 2qt + 3rt^2`
`a = (dv)/(dt) = 0 + 2q + 6rt`
At t = 2s; a = 2q + 6 × 2 × r
= 2q + 12r
= 2 × 4 + 12 × 5
= 8 + 60
= 68 m/s
Force = F = ma
= 2 × 68
= 136 N
APPEARS IN
संबंधित प्रश्न
A monkey of mass 40 kg climbs on a rope in given Figure which can stand a maximum tension of 600 N. In which of the following cases will the rope break: the monkey
(a) climbs up with an acceleration of 6 m s–2
(b) climbs down with an acceleration of 4 m s–2
(c) climbs up with a uniform speed of 5 m s–1
(d) falls down the rope nearly freely under gravity?
(Ignore the mass of the rope).
When a horse pulls a cart, the force that helps the horse to move forward is the force exerted by
A small block B is placed on another block A of mass 5 kg and length 20 cm. Initially, the block B is near the right end of block A (In the following Figure). A constant horizontal force of 10 N is applied to the block A. All the surfaces are assumed frictionless. Find the time that elapses before block B separates from A.
Calculate the tension in the string shown in the following figure. The pulley and the string are light and all the surfaces are frictionless. Take g = 10 m/s2.
Find the acceleration of the block of mass M in the situation shown in the following figure. All the surfaces are frictionless and the pulleys and the string are light.
Find the acceleration of the blocks A and B in the three situations shown in the following figure.
A block is kept on the floor of an elevator at rest. The elevator starts descending with an acceleration of 12 m/s2. Find the displacement of the block during the first 0.2 s after the start. Take g = 10 m/s2.
Two balls A and B of masses m and 2 m are in motion with velocities 2v and v, respectively. Compare:
(i) Their inertia.
(ii) Their momentum.
(iii) The force needed to stop them in the same time.
How can Newton's first law of motion be obtained from the second law of motion?
The correct form of Newton's second law is :
The linear momentum of a body of mass m moving with velocity v is :
A force of 10 N acts on a body of mass 2 kg for 3 s, initially at rest. Calculate : The velocity acquired by the body
What do you understand by the term momentum?
Use Newton's second law to explain the following:
We always prefer to land on sand instead of hard floor while taking a high jump.
A stone is thrown vertically upward with a velocity of 9.8 m/s. When will it reach the ground?
A ball is thrown upward and reaches a maximum height of 19.6 m. Find its initial speed?
In the previous problem (5.3), the magnitude of the momentum transferred during the hit is ______.
According to Newton's Second Law of Motion, what quantity is directly proportional to the applied force?
