Test: Motion - 2 - Year 11 MCQ

A red line on a speed-time graph generally signifies an object undergoing constant acceleration. In this context, the value of acceleration or deceleration magnitude is depicted, with the degree of slope on the line indicating the rate of acceleration. A steep slope on the line implies significant acceleration, while a gentle slope indicates minor acceleration.

Constant acceleration on a speed-time graph is typically shown as a non-horizontal straight line. This line helps visualize how the speed of an object changes over time at a constant rate. The slope of this line indicates the magnitude of acceleration, with steeper slopes representing higher rates of acceleration.

An upward curve with an increasing gradient on a speed-time graph would indicate increasing acceleration. This curve represents a scenario where the object is accelerating at a faster rate over time, leading to a steeper curve on the graph as the acceleration increases progressively.

A downward line on a speed-time graph usually indicates constant deceleration. This line illustrates how the speed of an object decreases over time, resulting in a negative acceleration. The shape of the curve in this scenario can vary based on whether the deceleration is constant, increasing, or decreasing.

In the absence of air resistance, objects falling without any external forces experience freefall acceleration, where they descend with a constant acceleration. This acceleration is typically around 9.8 meters per second squared near the Earth's surface, as observed by Galileo.

Objects falling through fluids in a uniform gravitational field experience two main forces: weight, which is due to gravity, and friction, such as air resistance. These forces act in opposite directions, affecting the motion of the falling object.

When a skydiver reaches terminal velocity, the forces acting on them are balanced, resulting in zero acceleration. At this point, the skydiver moves at a constant speed since the upward force of air resistance equals the downward weight force, leading to equilibrium in their motion.

Air resistance increases with the skydiver's speed during freefall. As the skydiver accelerates and gains speed, the air resistance they experience also increases, affecting their overall speed during the fall.

A skydiver reaches terminal velocity when the upward force of air resistance equals the downward weight force. Factors contributing to this equilibrium include the increased surface area, such as when the parachute is deployed, which leads to an increase in air resistance and a decrease in the skydiver's acceleration.

When a skydiver deploys the parachute during freefall, the increased surface area leads to higher air resistance. This increase in air resistance causes the skydiver's speed to decrease as they decelerate, moving towards a slower terminal velocity due to the balanced forces acting on them.