When Azaria tells her father that her bicycle is hard to pedal, he oils the chain. How does this make her bike easier to ride?
The oil reduces the friction force.
One example is trying to increase friction: A) spreading sand onto an icy road B) reducing the weight of an object C) pouring oil into the engine of a car D) waxing the underside of a surfboard
Find the correct example and explain why it increases instead of decreases friction.
What is A - spreading sand onto an icy road.
Ice is near frictionless but the sand can break the ice surface and provide grip for vehicles or people traveling over it.
Two students sit on a seesaw in a way that makes it horizontal (flat) and not move. When a third person pushes down on one side, that side moves down. When the seesaw isn't moving this is an example of BLANK but when the third person pushes, this is an example of BLANK.
1. ballanced forces
2. unbalanced forces
A runner measured the time it took him to run 5 km. What can he calculate from the distance and time measurements?
Speed
A child is jumping on a trampoline higher and higher, trying to touch the tree overhead. Identify the action and reaction of the child jumping on the trampoline.
Action: Child -> Trampoline
Reaction: Trampoline -> Child
What is the relationship between force and the mass of an object?
The greater the mass of an object, the greater the force needed to move it.
Identify and label the action and reaction forces (use your swappy arrows!!!)
ACTION: Stick figure -> Boat
REACTION: Boat -> Stick figure
Which will happen to an object if the forces acting upon it are unbalanced?
The object will accelerate.
This graph shows the change in position of an object over time. How can you describe the movement of the object after 3 seconds?
It returned to the starting point, <Bonus: slowing at the end.>
A car and truck are next to each other, slowing down to a stop applying the breaks at the same time.
1.Which object has more inertia,
2. why,
3. and what will happen to that object as a result?
1. The truck has more inertia
2. because it has more mass,
3. and it will take longer to stop.
A student observes their classmate propell a small and a large toy car up a ramp. The same amount of force was applied to each car. What would be the best hypothesis this student would expect to observe?
The large car will not travel as far as the small car.
OR
The small car will travel further than the large car.
DAILY DOUBLE!! Look at the graph below. What is the acceleration of the car?
0m/s2
If a train travels west at 80mph for 4 hours, what distance will the train travel? (speed = distance / time)
320 miles
Scientists discover a meteor moving 468km per minute traveling in a straight south to north direction..
1. What kind of rate description is this: speed, velocity or acceleration?
2. Convert to seconds.
3. Give the measurement including units and direction if applicable.
1. Velocity
2 and 3. 7.8m/s south to north
A weightlifter applies 5000N of force to a 500kg weighted bar. What will the acceleration of the bar be? Make sure to include your units!!
5000N/500kg equals..
10m/s2
DAILY DOUBLE!! Two carts are pushed up identical inclined planes. One cart A has a mass of 5kg while cart B has a mass of 10kg. Each has 10N of force applied. What is the acceleration of each cart, and, which one will accelerate faster?
Cart A 2m/s2
Cart B 1m/s2
Cart A accelerates faster!
DAILY TRIPLE! Gabriel walks 5 km in 10 minutes. If Gabriel walks 2.5 km at the same speed, which is the best estimate of the time this will take? (speed = distance / time)
5 minutes
What two pieces of information are needed to determine how fast a truck is traveling?
distance and time
A ball moves across a flat surface at 7 feet per second. If a student is asked to calculate the total distance traveled by the ball, what other information does the student need to know?
The total time the ball rolled.
Distance= speed x time
Describe the motion of each graph A to C.
**D is DOUBLE points for right, 100 points off for wrong!!!:
A. At Rest (not moving)
B. Constant Speed
C. Accelerating
D. Returning to start and slowing down.
A car traveled 60 miles in one hour, while a bus traveled 120 miles in two hours. Which best describes the motion of the vehicles? (speed = distance / time)
The bus and car are traveling the same average speed of 60mph!
A truck is traveling 70 mph with a heavy load in its trailer. After the truck is unloaded, it again travels 70 mph. The truck used only half the gas to go the same distance after it was unloaded. Which best explains why the truck used less gas after the truck was unloaded? (2nd law!!!)
The mass is less after the truck is unloaded. Thus it takes less force to accelerate and doesn't use as much fuel to get up to speed.
Which best describes the rate at which an object changes its POSITION over time?
speed
A police car drives at a constant speed of 100 miles per hour. How far can it travel in 10 hours?
D= Speed x Time
D= 100 m/h x 10 h
D= 1000 miles
The graph below shows the movement of an Earthworm. Gavin and Maddy observed an earthworm crawling on the sidewalk for four minutes. When did the earthworm move the greatest distance and how do you know?
From 0 to 1 min, because it covers more distance in less time (also acceptable, the slope is steeper on the distance time graph).