5.4 forces 🍽

Question 1

state Hooke’s Law

Answer 1

Hooke’s Law states that force is directly proportional to extension, provided the elastic limit has not been reached

Question 2

define upthrust

Answer 2

upthrust is the vertical force exerted by the surrounding fluid when a body is partially or fully submerged in a fluid. it is equal in magnitude and opposite in direction to the weight of the fluid displaced by the body

Question 3

state the conditions for equilibrium

Answer 3

1) resultant force acting on the body in any direction must be zero
2) resultant moment about any point of the body must be zero

Question 4

define moment

Answer 4

moment is the product of magnitude of the force and the perpendicular distance of the force from that point

Question 5

define torque of a couple

Answer 5

a couple consists of a pair of forces of equal magnitude but acting in opposite directions, whose lines of action are parallel but separate.
torque is the product of one of the forces and the perpendicular distance between the forces.

Question 6

state the principle of moments

Answer 6

for an object in equilibrium, the sum of clockwise moments is equal to the sum of anticlockwise moments about the same point

Question 7

define centre of gravity

Answer 7

the single point at which the entire weight of the body can be considered to act