9/27/23

Acceleration Calculations and
Net Force Diagrams

I'm sick. Here is basically what you would've gotten today if I wasn't gone.

​For the following problems use the formula for acceleration to calculate the missing piece of information.

Keep in mind!!!
I have rounded my answers slightly so pick the answer closest to what you got.

Meters per second squared is shown like this (m/s^2) so if you see that unit that is what it means.

Remember you principles of algebra

Pay attention to the units

Acceleration, Velocity and Displacement can all be negative or positive (vectors). Choose wisely....

Multiple Choice

A train crosses a checkpoint traveling at 100 m/s. It then gets a call that there are cows on the track a few miles ahead and they are going to have to stop. It takes them 120 seconds to do so. What is the trains acceleration?

• -0.833 m/s^2

• 8m/s^2

• 0.833 m/s

• 12000 m/s

Multiple Choice

Helga is traveling down the road at a brisk 34 m/s on her bike. She quickly speeds up to 45 m/s over a 18 second interval. What is Helgas acceleration?

• 4.39 m/s^2

• 0.61 m/s^2

• -0.61 m/s^2

• -4.39 m/s^2

Multiple Choice

Aaron is traveling down the road to visit his grandma. He starts his trip traveling at a rate of -3.4 m/s. He then realizes he is going to be late and changes his speed to -5.4 m/s. He does this all over the course of 6 seconds. What is his acceleration?

• 0.333 m/s

• -0.333 m/s^2

• 1.46 m/s^2

• 3 m/s^2

Multiple Choice

A tractor starts at rest on a brisk fall morning. It then speeds up at a rate of 4 m/s^2 for 40 seconds. What is the final velocity of the tractor?

• -160 m/s

• -160 m/s^2

• 160 m/s

• 0.1 m/s^2

Multiple Choice

A speed boat is traveling down the river at a velocity. It speeds up to 60 m/s at a rate of 3 m/s^2 for 20 seconds. What was the boats initial velocity?

• -1 m/s

• 60 m/s

• 0 m/s

• 1 m/s

Recall back to when we introduced talking about forces and I briefly talked about these

​

Net Forces and Force Diagrams

​Forces we will cover ***FYI Units are Newtons (N)*

• Gravity- fundamental force that causes an attraction between objects with mass.

• Applied- any force APPLIED onto one object by another object.

• Normal-the force that surfaces exert to prevent solid objects from passing through each other.

• Friction- the force that resists motion when the surface of one object comes in contact with the surface.

• Air Resistance- the force that acts in the opposite direction to an object moving through the air.

• Tension- the force transmitted through a rope, string or wire when pulled by forces acting from opposite sides.

• Spring- The force exerted by spring to restore its relaxed state.

​Forces acting on the object "even each other out"

This results in no net change in the object.

Balanced Forces

Forces applied on the object are not equal and will result in movement towards the overall net force.

Results in change in the object.

Unbalanced Forces

Example

Here we see 4 forces acting on this box.
There are 4000 Newtons applied upward and downward on the box which tells us that it probably won't move up or down.

There is also 1354 Newtons being applied leftward and 2356 Newtons rightward. This would tell us that the overall net force on this box is 1002 N in the right direction.

Multiple Choice

Using the image. What is the overall net force?

• 50 N left

• 50 N right

• 150 N right

• 350 N

Multiple Choice

What is the overall Net force

• 10 N

• 5 N right

• 5 N Left

• 0 N; No movement

Multiple Choice

What is the Net Force?

• 4 N

• 2 N up

• 2 N Right

• 2 N up and

  2 N right

Multiple Choice

According to this Force diagram which direction is the Net Force Pointed?

• Right

• Up

• Left

• Down

Multiple Choice

Using the force diagram what would the Net force be?

• 4 N up

• 6 N up

• No Movement

• 2 N right