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Mechanics

We will look at changes that involve motion of one form or another —running and jumping, throwing balls, lifting weights.

There are two big questions we must tackle to study how things change by moving:

  • How do we describe motion? How should we measure or characterize the motion

    if we want to analyze it mathematically?

  • How do we explain motion? Why do objects have the particular motion they do?

    Why, when you toss a ball upward, does it go up and then come back down rather than keep going up?

    What are the “laws of nature” that allow us to predict an object’s motion?

Kinematics deals with the concepts that are needed to describe motion. Dynamics deals with the effect that forces have on motion. Together, kinematics and dynamics form the branch of physics known as Mechanics.

What is the tipping angle for a 120 kg refrigerator, 80 cm by 200 cm, when it is placed on end?
A bowler applies a constant net force of 100 N on a 5-kg bowling ball over a time period of 1.5 s before he releases the ball. The ball starts from rest. What is its final velocity?
A rocket goes from rest to 9.6 km/s in 8 min. The rockets mass is 8.0x106 kg. Assuming a constant acceleration, what is the net force acting on the rocket?
A car moves in a horizontal circle with a radius of 10 m. The tangential velocity of the car is 30 m/ s. What is the cars acceleration? If the car in has a mass of 1000 kg, then what is the force of friction acting on the car?
1. Determine the force of gravity keeping the Earth in its orbit around the sun. 2. A 222kg weather rocket reaches a maximum height of 32km above the Earths surface determine: The amount of gravitational potential energy at its maximum height. It’s speed
A girl pushes a 10-kg box from rest across a horizontal floor with a force of 50 N. The force of friction opposing her is 45 N. If the box uniformly accelerates from rest to a final velocity of 2.0 m/s, how much time did it take to get to that velocity?
At the very beginning of a dash, a 70-kg runner accelerates uniformly from rest to 10 m/s in 0.5 s as she moves in the positive direction. What is the net force acting upon the runner?
A bicycle wheel has a radius of 0.5 m. When it spins, it completes one full turn in 1.6 s. A pebble wedged in the tread has a mass of 10 g. What is the centripetal force on the pebble?
You swing a 100-g object attached to a 2-m string in a circle above your head. The speed of the object is 12 m/s. What is the centripetal force on its mass?
A car with a mass of 1000 kg travels at 30 m/s. The driver applies his brakes for a uniform deceleration and comes to a complete stop in 60 m. Assuming that the forward motion is positive, what is the magnitude and direction of the net force

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Subcategories

Kinematics (Speed, Velocity and Acceleration) 42

Dynamics (Forces and Newton's Laws of Motion) 54

Simple Harmonic Motion 15

Momentum 42