forces

Question 1

what does a force do

Answer 1

a force may produce a change in the size and shape of a body

Question 2

what does hooke’s law state

Answer 2

the extension or compression produced in a spring is directly proportional to the load applied to it until its elastic limit

Question 3

what is hookes law formula

Answer 3

force = spring constant x extension

Question 4

what is friction

Answer 4

• contact force
• force that opposes the motion of an object
• air resistance is a frictional force

Question 5

friction formula

Answer 5

force = mass x acceleration

Question 6

what is circular motion

Answer 6

when an object moves in a circular path, even if it travels at a constant speed the direction of its velocity changes at every point

Question 7

what are the 3 factors affecting the magnitude of the centripetal force

Answer 7

• mass of the object: as this increases the force increases
• speed of the object: as speed increases the force increases
• radius of the circle path: as the radius decreases the force required increases

Question 8

formula for moments

Answer 8

moment = force x perpendicular distance of the line of action of the force from the pivot

Question 9

what is equilibrium

Answer 9

when an object continues to be in its state of rest or uniform motion

Question 10

how does an object reach equilibrium

Answer 10

• the forces acting on the object are balanced (no resultant force)
• the net resultant moment acting on an object is 0 (sum of clockise moments equal to sum of anticlockwise moments)

Question 11

what is the principle of moments

Answer 11

for an object to be in rotational equilibrium, the sum of the clockwise moments should be equal to the sum of the anti-clockwise moments

Question 12

what is centre of mass

Answer 12

the point inside or outside an object where the entire mass of an object can be assumed to be concentrated. It is the point through which the weight of an object acts
for regualr objects its located at the geometrical centre

Question 13

the relationship between centre of mass and stability

Answer 13

• closer the centre of the mass of an object to its base of support, the greater the stability of the object
• wider the base of support of an object, the greater the stability of an object

Question 14

what are scalars

Answer 14

only have magnitude

Question 15

what are vectos

Answer 15

magnitude and direction