Forces and energy est

Question 1

(Est)What is force?

Answer 1

A force is an action that can change the motion of an object or deform it by pushing or pulling
on it. A force is exerted by one object on another and in one direction:

Question 2

(est)What is a force expressed in?

Answer 2

Force is expressed in Newtons (N). 1 Newton is equal to the force required to make a 1 kg
object accelerate at a rate of 1 m/s 2 .

Question 3

(est)What is equilibrium?

Answer 3

not moving, constant speed

Question 4

(est)What is gravitational force?

Answer 4

Gravitational force is a force of attraction acting between all objects. This force depends
on the objects’ masses and the distances between them.

Question 5

(est)How does the mass affect the force of attraction?

Answer 5

The higher the mass, the greater the
force of attraction.

Question 6

(est)Do all planets have the same force of attraction?

Answer 6

no

Question 7

(est)What is an electromagnetic force?

Answer 7

An electromagnetic force is a force of attraction or repulsion between two objects with
an electrical charge or magnetic poles.

Question 8

(est) what is friction?

Answer 8

Friction is a force that prevents two objects from slipping over each other

Question 9

(Est) What is adhesion?

Answer 9

Adhesion is the phenomenon by which two surfaces remain in contact with each other without
slipping.

Question 10

(est) What is the strength of adhesion-dependent on?

Answer 10

 The nature of the materials in contact.
 The presence of a lubricant.
 Temperature
 The state of the surfaces
 The strength of the perpendicular force exerted on the surface.

Question 11

(est) what is effective force?

Answer 11

The force that affects the motion of an object is
called the effective force (p.88).

Question 12

(est)When is work done?

Answer 12

Work is done when a force applied to an object causes it to move in the same direction as the
force or one of its components.

Question 13

(est)Brad is pulling his daughter Ashley on a sleigh. The rope is at an angle of 47 with the
horizontal. Brad has a mass of 87kg and exerts a force equal to his weight, and pulls his
daughter for a total of 1.0km.
how much work is done by brad?

Answer 13

w=581471.8

Question 14

(est)what is a Joule?

Answer 14

the SI unit of work or energy, equal to the work done by a force of one newton when its point of application moves one meter in the direction of action of the force

Question 15

(est) What is kinetic energy?

Answer 15

A moving object has the capacity to do work and possesses energy due to its motion. This
energy is called kinetic energy.

Question 16

(est)If the mass of an object is doubled what effect does this have on its kinetic energy?

Answer 16

If the mass of the object is doubled, its kinetic energy is also doubled. If the objects velocity is
doubled, then it`s kinetic energy quadruples.

Question 17

(Est)A baseball pitcher throws a ball weighing about 150 g to another player. What is the kinetic
energy of the ball if, at the moment it is caught, its velocity is 5 m/s?

Answer 17

25m/s

Question 18

(est) What is potential energy?

Answer 18

Gravitational potential energy is the
energy reserve of an object based on its
mass and height.

Question 19

(est) What is mechanical energy?

Answer 19

the sum of kinetic energy and potential energy.

Question 20

(est) What is the relationship between potential energy and kinetic energy?

Answer 20

potential energy transforms into kinetic energy, and kinetic energy converts into potential energy, and then back again.