Question

scenario
a dog pulls forward with 30 n.
friction pulls backward with 10 n.
calculation
net force & direction
engine pushes rocket up with 500 n.
gravity pulls rocket down with 300 n.
real world examples
read the situations below and choose the best answer based on your understanding of forces.

1. a car is accelerating onto the highway. the force of the engine pushing forward is greater than the force of air resistance pushing back. this is an example of:

a) balanced forces
b) unbalanced forces
c) zero net force
d) gravity only

1. an airplane is flying at a steady speed and height. the lift balances the weight, and the thrust balances the drag. what is the net force?

a) 100 n
b) 1000 n
c) 0 n
d) it depends on the size of the plane

1. in a tug of war game, one team pulls with 250 n and the other pulls with 200 n. what will happen?

a) the rope will not move.
b) the rope will move toward the 200 n team.
c) the rope will move toward the 250 n team.
d) the rope will break.
check your understanding
use the diagram description to answer the question below regarding the box.

Explanation:

Step1: Calculate dog's net force

Define forward as positive: $F_{net} = 30\ \text{N} - 10\ \text{N} = 20\ \text{N}$

Step2: Calculate rocket's net force

Define up as positive: $F_{net} = 500\ \text{N} - 300\ \text{N} = 200\ \text{N}$

Step3: Analyze question 1

Unbalanced forces cause acceleration.

Step4: Analyze question 2

Balanced forces give 0 net force.

Step5: Analyze question 3

Net force favors the 250 N team.

Answer:

Table Completion:

1. Dog Scenario

Calculation: $30\ \text{N} - 10\ \text{N} = 20\ \text{N}$
Net Force & Direction: 20 N forward

1. Rocket Scenario

Calculation: $500\ \text{N} - 300\ \text{N} = 200\ \text{N}$
Net Force & Direction: 200 N upward

Real World Examples:

1. b) Unbalanced forces
2. c) 0 N
3. c) The rope will move toward the 250 N team.