Forces and Motion
What two main forces act on a soccer ball after its kicked into the air?
Gravity and air resistance
What two factors determine an object’s kinetic energy?
Mass and Speed
What is air resistance?
A force that opposes motion through air
What is the independent variable in the kick speed vs ball mass investigation?
Ball mass
Why might a faster baseball cause more injury than a slower one, even if both have the same mass?
the faster the ball the more kinetic energy it has, which causes more damage in a collision
When a player increases the force of a kick, what happens to the ball’s acceleration?
It increases
Which will have more kinetic energy - a lighter ball moving fast or a heavier ball moving slowly?
Depends, both can be equal, but faster speed usually has more effect.
How does a headwind affect a soccer ball’s speed?
It slows it down
What is the dependent variable in that same investigation?
Kick speed
Why might players choose a lighter ball on windy days?
Less air resistance and easier control
What happens to the ball’s motion when the net force equals zero?
If a player kicks two soccer balls with the same force but one ball is heavier, which one travels slower?
The heavier one
What happens to a soccer ball‘s motion when kicked with a tailwind?
It goes faster/farther
If two objects collide, how can energy be transferred between them?
Energy transfers through the contact forces between them
Why do materials that deform less produce higher peak forces?
They absorb less energy and return more energy to motion
Why does the ball eventually stop rolling on the field even if no one touches it?
Friction between the ball and the grass slows it down
As the mass of the ball increases, what happens to its kick speed if the same force is applied?
It decreases
Why does air resistance have less effect at a higher altitudes?
There are fewer air particles to push against it.
Why do scientists repeat trials in an investigation?
To reduce errors and increase accuracy
How might altitude affect a long- range shot during a match?
The ball will travel farther in thinner air
Draw or describe a free-body diagram for a soccer ball that has just been kicked forward.
Arrows for gravity (down), air resistance (back), and motion (forward)
Explain using energy transfer why a ball with more mass might not travel as far.
More energy goes into moving its mass, leaving less for increasing speed.
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)
Why do we graph data when doing experiments like this?
To visualize relationships and patterns between variables
What factor would you focus on most for improving kick performance - mass, material, or speed?
Speed (has biggest effect on kinetic energy)