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# Tag Archives: laws of motion

## Sequence of Learning Physics

In what sequence should these chapters be prepared for my exams:-

units and dimensions,kinematics,laws of motion,work power and energy,motion of system of particles and rigid body dynamics,gravitation.

Apoorv Katoch asked

Answer:

It is better to follow the same pattern as given in NCERT text book

## Numerical Problem from Laws of Motion

An 8000 kg engine pulls 40000 kg train alonged a level track and gives an acceleration of 1.2m/s2. Find the accelaration produced by same engine on a train of mass 16000kg?

**Answer**:

Force exerted by the engine = mass of train x acceleration = 40000 x 1.2=48000N

When the same engine pulls a 16000 kg train, the acceleration = 48000/16000=3m/s2

## A few numerical problems from laws of motion

- A worker pulls a 200. N packing crate with an applied force of 55.0 N. The crate accelerates at a rate of 0.250 m/s(squared). What is the coefficient of kinetic friction between the crate and the factory floor?
- A student pulls a 150. N sled up a 28 degree slope at a constant speed by applying a force of 100. N. Near the top of the hill he releases the sled. With what acceleration does the sled go down the hill?
- A 200. N crate rests on a ramp; the maximum angle just before it slips is 25 degrees with the horizontal. What is the coefficient of static friction between the crate and the surface of the ramp?
- A man pulls a sled with a weight of 200. N with a constant velocity across a horizontal snow surface. If a force of 80N is being applied to the sled rope at an angle of 53 degrees to the ground, what is the coefficient of friction between the sled and the ground?
- A jet plane is flying with a constant speed along a straight line at an angle of 30degree above the horizontal. The weight of plane is 86 500N. Its engine provides a forward thrust T of 103 000N. The lift of force L(directed perpendicular to the wings)and the force R of air resistance (directed opposite to the motion)act on the plane. Find L & R

## Terminal Speed and Newton’s Laws of motion

What is terminal speed? When a skydiver has reached terminal speed, what is the air resistance equal to? What is the skydivers acceleration?