Movement and Position Flashcards
What is speed?
Distance travelled per unit time. Measured in metres per second (m/s). A scalar quantity (has magnitude but no direction).
What is the formula for average speed?
Average speed = total distance / total time. Used to calculate overall speed over a journey.
Define velocity.
Speed in a given direction. A vector quantity (has both magnitude and direction).
Define acceleration.
Change in velocity per unit time. Measured in metres per second squared (m/s²). Can be positive (speeding up) or negative (deceleration).
Write the formula for acceleration.
Acceleration (a) = (final velocity - initial velocity) / time taken. a = (v - u) / t. Measured in m/s².
State the SI units of distance, time, speed, velocity, and acceleration.
Distance: metres (m). Time: seconds (s). Speed & velocity: metres per second (m/s). Acceleration: metres per second squared (m/s²).
Provide examples of scalar and vector quantities.
Scalar: Speed, distance, mass, time, energy, temperature. Vector: Velocity, displacement, force, acceleration, momentum.
What is air resistance?
A type of frictional force that opposes the motion of an object through air. Increases with speed and surface area. Acts in the opposite direction to movement, reducing acceleration. Eventually balances weight, leading to terminal velocity.
What is friction?
A force that opposes motion between two surfaces in contact. Converts kinetic energy into heat energy. Can be reduced using lubrication (e.g., oil or grease).
How do you plot and explain a distance-time graph?
Distance on the y-axis, time on the x-axis. Gradient represents speed (steeper gradient = higher speed). A straight diagonal line indicates constant speed. A horizontal line indicates the object is stationary. A curved line represents acceleration or deceleration.
What does a negative gradient in a displacement-time graph indicate?
Returning to the starting point. Object is moving in the opposite direction.
What does a horizontal line in a displacement-time graph mean?
The object is stationary.
How do you plot and explain a velocity-time graph?
Velocity on the y-axis, time on the x-axis. Gradient represents acceleration (steeper = higher acceleration). A horizontal line indicates constant velocity. A negative gradient represents deceleration. Area under the graph represents distance travelled.
What does the gradient of a velocity-time graph represent?
Acceleration. Gradient = (change in velocity) / (time taken).
How do you determine acceleration from the gradient of a velocity-time graph?
Acceleration = change in velocity / time taken. Determined from the slope of the graph.
What does the area under a velocity-time graph represent?
Distance travelled. Found by calculating the area under the curve.
How do you determine distance from the area under a velocity-time graph?
Calculate the area under the graph. Use geometry (triangles and rectangles) to find distance.
Describe an experiment to measure the speed of an object.
Use a measured track and a stopwatch. Measure the total distance travelled. Record the time taken to travel that distance. Use the formula: speed = distance/time. Repeat the experiment and take an average for accuracy.
How can light gates improve accuracy in speed measurement?
Removes human reaction time error. Provides precise electronic time readings.
Describe an experiment to investigate the motion of everyday objects such as toy cars or tennis balls.
Set up a ramp with a smooth surface. Mark equal intervals along the ramp. Release the object from the top without pushing. Use a stopwatch or light gates to measure time taken at intervals. Calculate speed at different points and plot a graph.
What is the equation for uniform acceleration?
v² = u² + 2as. Used when acceleration is constant.
What is the acceleration of free fall near Earth?
9.8 m/s² (approximated as 10 m/s² in calculations).
What is terminal velocity?
The constant velocity reached when air resistance balances weight.
What factors affect terminal velocity?
Weight of the object. Air resistance. Surface area of the object. Shape of the object.
Describe an experiment to measure reaction time.
Hold a ruler above a subject’s hand. Drop the ruler without warning. Measure the distance it falls before being caught. Use the formula to calculate reaction time. Repeat the experiment and take an average.
Explain the difference between instantaneous and average speed.
Instantaneous speed: Speed at a specific moment. Average speed: Total distance divided by total time.
What is the relationship between acceleration and mass?
Inversely proportional.
What is the relationship between acceleration and force?
Directly proportional.
How do parachutes help a falling object?
Increase air resistance. Reduce terminal velocity.
What is the principle behind Newton’s first law of motion?
Objects remain at rest or in uniform motion unless acted upon by an external force.
Describe how to investigate acceleration using a trolley on a ramp.
Set up a ramp with a smooth surface. Place a light gate at two points along the ramp. Release the trolley from the top without pushing. Record time taken to pass through each light gate. Use acceleration formula a = (v - u) / t.
Why do objects of different masses fall at the same rate in a vacuum?
No air resistance, so only gravity acts on them.
How can accuracy in motion experiments be improved?
Use electronic sensors like motion sensors. Minimize human reaction time errors.
What is the function of a ticker timer in motion experiments?
Marks dots on paper tape at regular intervals. Used to measure speed and acceleration.
