[Part 2] P8- Forces in balance 🚂🏎️

Question 1

What is the resultant force ?

Hint: single, effect

Hint #2: object’s speed

Answer 1

• the resultant force, is a single force that has the same effect, as all of the original forces acting together.
• [; it also causes an object’s speed to change or can change its direction]

Question 2

How can the reluctant force be calculated?

Hint: ➖️

Answer 2

• the resultant force can be calculated by:
• subtracting the smaller force, from the larger force.

Question 3

What does it mean if the forces are balanced ?

Hint: resultant force

Answer 3

• if the forces are balanced, this means there the resultant force is zero.
• [because, they cancel each other out]

Question 4

What is a free-body diagram ?

Answer 4

• a free-body diagram, is a diagram that shows the forces acting on an object, without any other objects or forces shown.
• in a free-body diagram, the object is shown as a point and the forces are drawn as arrows [starting at the point].

Question 5

• Fill in the gaps: In a free-body diagram, The length of the ______= size of the force and the direction of the arrow= _________ of the force.

Answer 5

• The length of the arrow= size of the force and the direction of the arrow= direction of the force.

Question 6

What does altitude mean ? ✈️

Hint: height

Answer 6

• altitude, means the height above the ground.

Question 7

What does moving at constant altitude 🆚 constant velocity mean ? ✈️

Hint: opposite direction, balanced forces

Answer 7

• constant altitude, means there must be a force the same magnitude as the weight, but acting in the opposite direction.
• ; is something is moving at constant velocity, the forward and backwards forces must be balanced.

Question 8

What’s the checklist to use, when identifying pair of forces ? 🍎

Hint: contact, equal size, different object

Answer 8

1) the two forces must be the same type of force- [contact or non-contact]

2) the two forces are equal sizes; in opposite directions.

3) and each force, acts on a different object.

Question 9

Describe the effects of zero and non-zero resultant forces on objects

Hint: speed up 🆚️ steady speed

Answer 9

• non-zero resultant forces, mean the moving objects could speed up
• ; zero resultant forces mean that the object will stay at a steady speed as it has no resultant force, and will eventually slow down.

Question 10

An ice skater is skating along ice. State the forces ⛸️

Answer 10

• backwards resultant forces
• drag/air resistance [backwards]
• gravity
• normal contact force

Question 11

What is Newton’s first law [of motion] ? 🍏

Hint: zero resultant force= object

Answer 11

• Newton’s first law is:
• if the resultant force acting on a stationary object is zero, them the object will remain stationary
• ; if the resultant force acting on a moving object is zero, then the object will continue moving in the same direction, at the same speed [with the same velocity]

Question 12

When will the velocity of an object change ?

Hint: resultant force

Answer 12

• the velocity of an object will only change if, a resultant force is acting on the object.

Question 13

What is Newton’s third law [of motion] ? 🍏

Answer 13

• newton’s third law of motion is:
• whenever two objects interact, the forces they exert on each other are equal and opposite.

Question 14

What is an example of Newton’s third law? 🛶

Answer 14

• a person in a canoe, is using a paddle to push on the water; at the same time, the water pushes back on the paddle.
• This is an example of Newton’s third law because, whenever two objects interact, the forces they exert on each other are equal and opposite.

Question 15

What is another example of Newton’s third law? 🛹

Hint: push force

Answer 15

• when a skateboarder jumps off a skateboard, they apply a push force onto the skateboard- causing the skateboard, to move to the right.
• ; at the same time, the skateboard pushes back on the skateboarder [this force is equal in magnitude, though opposite or direction]- then causing the skateboard, to move to the left.
• This is an example of Newton’s third law because, whenever two objects interact, the forces they exert on each other are equal and opposite.

Question 16

Give another example of Newton’s third law 🚀

Answer 16

• when a rocket fired, the chemical reaction produces a downward push force on the hot exhaust gases.
• ; the hot exhaust gases, exert an equal force on the rockets but acting in the opposite direction [upwards]
• This is also an example of Newton’s third law because, whenever two objects interact, the forces they exert on each other are equal and opposite.