Forces

Question 1

Definition of a Force & SI unit

Answer 1

That which causes an object to experience a change in: shape or size or location/position/motion or temperature

SI unit- Newton,N

Question 2

Two Main Categories of Forces

Answer 2

•Contact Forces- those in which the bodies involved must be physically touching in order for force to act eg. Friction
•Non-contact Forces/Action at a distance forces- The bodies involved DO NOT physically touch or forces that act between two bodies that are not physically touching eg. Magnetic forces

Question 3

Define Gravitational Force

Answer 3

-An attractive force that exists between two bodies due to their masses
-The Gravitational Force of a planet on an object is the object’s weight
- Gravitational Force is a NON-CONTACT force

Question 4

Define Magnetic Force

Answer 4

• an attractive or repulsive force that exists between bodies due to their magnetic polarities
• Magnetic Force is a NON-CONTACT force

Question 5

Define Electrostatic Force

Answer 5

-An attractive or repulsive force that exists between bodies due to their electric charges
-Electrostatic Force is a NON-CONTACT force

Question 6

Define Nuclear Force

Answer 6

-Extremely strong attractive forces which bind together the subatomic particles of an atomic nucleus
-Nuclear Force is a NON-CONTACT force

Question 7

Define Elastic Force

Answer 7

• Restoring forces produced by an object when it is stretched or compressed
• Elastic Force is a CONTACT force

Question 8

Define Mechanical Force

Answer 8

• those that exist between bodies in contact
• Mechanical Force is a CONTACT force

Question 9

Define Expansion Force (E.g. of Elastic Forces)

Answer 9

• The force found in a compressed spring, a squashed material or a heated object as it tries to expand

Question 10

Define Tension (E.g. of Elastic Forces)

Answer 10

• The force that is transmitted through a string, rope, wire etc. when it is pulled tight by force acting from opposite ends

Question 11

Define Friction (E.g. of Mechanical Forces)

Answer 11

• A mechanical force that opposes the relative motion of surfaces or bodies in contact with each other

Question 12

Define Upthrust (E.g. of Mechanical Forces)

Answer 12

• The BUOYANCY which all objects experience when immersed in a fluid (liquid or gas)

Question 13

Define The Normal Force (E.g. of Mechanical Forces)

Answer 13

• the SUPPORT force exerted upon an object that is in contact with another stable object
• the Normal Force acts with equal magnitude in the opposite direction to the perpendicular force acting on the surface at that point
• in physics, the word normal means ‘perpendicular to’ and so the Normal Force always acts at right angles to the surface