Exam 2: Kinetics of Linear Motion

Any two objects exert a gravitational force of attraction on each other. The magnitude of this force is inversely proportional to the square of the masses of the two objects and proportional to the distance between them.

Two basketballs are thrown across the court. Basketball A is thrown at twice the velocity of basketball B. Both basketballs have the same mass. In this case basketball B has the greater momentum.

A bobsleigh (mass = 430 kg) is pushed across a horizontal (ice) surface with a horizontal force of 1927 N. If the coefficient of static friction (µs) and coefficient of dynamic (kinetic) friction (µk) between the bobsleigh and the ice are 0.071 and 0.068 respectively, what is the friction force between the bobsleigh and the ice whilst being pushed?

What would be the weight of a 10kg object on Earth at sea-level in England?

The linear momentum possessed by an object is a measure of what?

The acceleration due to the pull from the mass of the Earth for all objects close to the Earth's surface, (gravity) is said to be what?

A training shoe is raised on a hinged surface (inclined plane), until it begins to slide. Immediately before the shoe begins to slide the angle of the surface to the horizontal is 47°. What is the coefficient of static friction (µs) between the shoe and the surface?

A rugby union player with a mass of 90 kg leaves the ground in preparation for a line out with a vertical velocity of 2.3 m/s. What is his vertical momentum at (i) the instant of take off, and (ii) the highest point of his jump.

An athlete weighs 648 N and runs at a 15.48 km/hr. What is their momentum?

Which of the following situations would be true according to Newton's law of acceleration?

Forces always act in single isolation.

According to Newton's law of gravitation, a large mass such as the Earth exerts a gravitational pull on smaller masses (such as people and objects), but we don't exert any such gravitational force on the Earth.

Briefly describe the impulse-momentum relationship.

Which answer is true regarding the definition of weight:

A cricketer (mass = 85 kg) leaps up to catch a ball (mass = 0.16 kg) travelling to the boundary at 27 m/s. Assuming the catch is successful what is horizontal velocity of the player and ball immediately after the catch is taken, before the player lands on the ground?

The inertia of an object is directly related to its mass.

A bobsleigh (mass = 430 kg) is pushed across a horizontal (ice) surface with a horizontal force of 1927 N. If the coefficient of static friction (µs) and coefficient of dynamic (kinetic) friction (µk) between the bobsleigh and the ice are 0.071 and 0.068 respectively, what is the maximal friction force between the bobsleigh and the ice?

Which of the following sports would be least likely to be affected significantly by a 'tail wind'

A bobsleigh (mass = 430 kg) is pushed across a horizontal (ice) surface with a horizontal force of 1927 N. If the coefficient of static friction (µs) and coefficient of dynamic (kinetic) friction (µk) between the bobsleigh and the ice are 0.071 and 0.068 respectively, what is the horizontal acceleration of bobsleigh?

A cricket ball (mass = 0.16 kg) travels towards a catcher with a horizontal velocity of 30 m/s. What is its horizontal momentum immediately before it is caught?