Forces & Motion
What are two main forces that can act on a soccer ball after it’s kicked into the air?
Gravity and air resistance
What two major factors determine an object’s kinetic energy? (We did 2 investigations to figure out which matters more)
Mass and speed
What is air resistance?
A force that opposes motion through air
What tool would you use to measure the speed of a kicked ball?
Radar gun or motion sensor
When a player increases the force of a kick, what happens to the ball’s KE?
It increases
If a player kicks two soccer balls with the same force but one ball is heavier, which one travels slower?
The heavier one
How does a headwind affect a soccer ball’s speed?
It slows it down
What would be the independent variable in an investigation that is comparing different kick speeds vs a 1 kg ball?
kick speed
What happens to the ball’s motion when the friction force is higher than the push force?
It wont move/move really slow
Which will have more kinetic energy — a lighter ball moving fast or a heavier ball moving slowly?
Ball moving faster
What happens to a soccer ball’s motion when kicked with a tailwind?
It goes faster/farther
What is the dependent variable in a investigation determining how much sunlight effects the growth of sun flowers?
The plant growth
Why does the ball eventually stop rolling on the field even if no one touches it?
Friction between the ball and grass slows it down
As the mass of the ball increases with every kick, what happens to its speed if the same force is applied each time?
It decreases
Why does air resistance have less effect at higher altitudes?
There are fewer air particles to push against
Why do scientists repeat trials in an investigation?
To reduce errors and increase accuracy
Draw a free-body diagram for a soccer ball that has just been kicked forward in the air.
Arrows for gravity (down), air resistance (back), and motion (forward)
Draw a diagram using arrows to show the difference between an object hitting its elastic limit vs breaking point.
Breaking point: Bigger arrow, damage shown
Elastic limit smaller arrow, deformation
If two identical balls are kicked the same but one is in Denver and one is at sea level, which travels farther?
The one in Denver (less dense air = less drag/resistance)
Why do we graph data when doing experiments?
To visualize relationships and patterns between variables