37 Questions
Force is a scalar quantity.
False
The S.I. unit of velocity is meter per second squared.
False
Friction is a type of contact force.
True
Gravity is an example of a contact force.
False
Lift is a type of air resistance.
True
The slope of a distance-time graph represents velocity.
True
Newton's second law of motion relates force, mass, and velocity.
False
The work input is always equal to the work output in a machine.
False
A girl walks 200m N, then 300m W then 150m N, then 200m E, then 100m N, then 100m E. The displacement of the girl is zero.
True
A car passes a cyclist traveling at 15m/s, from the frame of reference of the cyclist, the car appears to be traveling at 7m/s.
False
A naughty boy running west at 4m/s on a people mover moving east at 1.5m/s has a velocity relative to a person standing on the carpeted floor of 2.5m/s west.
True
346cm is equal to 3.46m.
True
A car accelerating from 0 to 15m/s in 30 seconds has an acceleration of 0.5m/s^2.
True
If acceleration is zero, velocity must also be zero.
False
A runner completing an 800 meter race in 90 seconds has an average speed of 8.89m/s.
True
Gravity is not a type of friction.
True
Momentum is a product of an object's mass and velocity. Since the velocity is zero, the momentum is also zero.
True
A velocity vs. time graph of a car traveling down the street appearing as a straight line sloping upwards indicates that the car's acceleration is constant.
True
A jaguar accelerating from 0 to 10.3m/s in 3.0 seconds has an acceleration of 3.43m/s^2.
True
The force that opposes your push when you're unable to move an object is gravity.
False
Air resistance is the force that acts on a projectile besides gravity.
True
Mass and weight are exactly the same thing.
False
Rolling friction is always greater than static friction.
False
Objects in free fall eventually reach a constant velocity due to air resistance.
True
If the input force of a machine is less than the output force, then the input distance is greater than the output distance.
True
A fixed pulley is an example of a compound machine.
False
The force exerted by the tab to open a soda can is greater than the force applied by the person to the tab.
True
A screwdriver is an example of a lever.
True
A wheel chair ramp is an example of an inclined plane.
True
A nutcracker is an example of a wedge.
True
The force required to push a full shopping cart is less than the force required to push an empty one due to Newton's third law.
False
The acceleration of a 0.2 kg baseball thrown with a force of 30N is 150 m/s^2.
True
A WWF wrestler with a mass of 157 kg weighs approximately 1550 N.
True
The momentum of a 4.7 g bullet shot from a gun at 1600 m/s is greater than the momentum of a baseball with a mass of 150g thrown at 39m/s.
True
The reaction force in a balloon car is the force exerted by the air molecules on the balloon.
True
Bernoulli's principle states that the pressure of a fluid decreases as its velocity increases.
True
The buoyancy force on an object is equal to its weight when it is suspended.
True
Study Notes
Physics Exam Study Guide
Terms and Concepts
- Vector vs Scalar Quantity:
- Vector: has magnitude and direction
- Scalar: has only magnitude
- Motion:
- Frame of Reference: a fixed point from which motion is measured
- Distance vs Displacement:
- Distance: total length of path traveled
- Displacement: shortest distance between initial and final positions
- Speed vs Velocity:
- Speed: scalar quantity, rate of change of distance
- Velocity: vector quantity, rate of change of displacement
- Instantaneous Speed vs Average Speed:
- Instantaneous Speed: speed at a specific point in time
- Average Speed: total distance traveled divided by time
- Distance vs Time Graphs:
- Slope of the graph represents velocity
- Acceleration:
- Rate of change of velocity
- Can be calculated using the formula: a = Δv / Δt
- Velocity vs Time Graphs:
- Slope of the graph represents acceleration
- Force:
- Push or pull that causes an object to change its motion
- Newton's Laws of Motion:
- First Law: Inertia, an object at rest stays at rest, an object in motion stays in motion
- Second Law: F = ma, force is equal to mass times acceleration
- Third Law: Every action has an equal and opposite reaction
- Work and Energy:
- Work: force applied over a distance
- Energy: ability to do work
- Machines:
- Simple Machines: lever, pulley, wheel and axle, inclined plane, wedge, screw
- Compound Machines: combination of simple machines
- Momentum:
- Product of an object's mass and velocity
- Pressure:
- Force per unit area
- Bernoulli's Principle:
- Faster moving fluids have lower pressure, slower moving fluids have higher pressure
- Buoyancy and Buoyancy Force:
- Upward force exerted on an object by a fluid (liquid or gas)
- Archimedes' Principle: buoyancy force is equal to the weight of the fluid displaced
- Friction:
- Force that opposes motion between two surfaces in contact
- Types: static, sliding, rolling, fluid
Formulas
- Average Velocity or Speed:
- v_avg = Δx / Δt
- Average Acceleration:
- a_avg = Δv / Δt
- Acceleration:
- a = F / m (Newton's Second Law)
- Weight:
- W = mg (mass times acceleration due to gravity)
- Momentum:
- p = mv (mass times velocity)
- Pressure:
- P = F / A (force per unit area)
- Work:
- W = F × d (force times distance)
- Power:
- P = W / t (work divided by time)
Review Questions
- Questions 1-44: various physics concepts and problems
Review key physics concepts for 8th grade science exam, including vector and scalar quantities, motion, distance, speed, velocity, acceleration, and graph interpretation.
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