Additional: Acceleration And Velocity

1. The units of acceleration are:-

Metres

Metres per second

Metres per second squared

Joules

Newtons

The units of acceleration are measured in meters per second squared. This unit represents the change in velocity per unit of time. It indicates how much an object's speed changes each second. The term "meters per second squared" specifically refers to the rate at which an object's velocity increases or decreases over time. This unit is commonly used in physics to describe the acceleration of objects in motion.

Explanation

The units of acceleration are measured in meters per second squared. This unit represents the change in velocity per unit of time. It indicates how much an object's speed changes each second. The term "meters per second squared" specifically refers to the rate at which an object's velocity increases or decreases over time. This unit is commonly used in physics to describe the acceleration of objects in motion.

2. A car accelerates at 6m/s2 for 4s. If it starts at rest its final speed is:-

24m/s

1.5m/s

0.67m/s

9m/s

156m/s

The car accelerates at a rate of 6m/s2 for 4 seconds. To find the final speed, we can use the formula v = u + at, where v is the final velocity, u is the initial velocity (which is 0 in this case), a is the acceleration, and t is the time. Plugging in the values, we get v = 0 + (6m/s2)(4s) = 24m/s. Therefore, the correct answer is 24m/s.

Explanation

The car accelerates at a rate of 6m/s2 for 4 seconds. To find the final speed, we can use the formula v = u + at, where v is the final velocity, u is the initial velocity (which is 0 in this case), a is the acceleration, and t is the time. Plugging in the values, we get v = 0 + (6m/s2)(4s) = 24m/s. Therefore, the correct answer is 24m/s.

3. A car travelling at a constant speed around a roundabout is accelerating because:-

The car is slowing down

The car is speeding up

The car is not changing speed

The car is changing direction

The car is decelerating

The car is changing direction because when it is going around a roundabout, it is constantly turning and following the curvature of the road. Even though the speed of the car may remain constant, the direction in which it is moving is continuously changing, which is considered as acceleration.

Explanation

The car is changing direction because when it is going around a roundabout, it is constantly turning and following the curvature of the road. Even though the speed of the car may remain constant, the direction in which it is moving is continuously changing, which is considered as acceleration.

4. An aircraft on the runway accelerates at 8m/s2 from rest until it reaches its take-off speed of 60m/s. How long does it take to reach this speed?

68s

1.1s

480s

7.5s

48s

The aircraft accelerates at a constant rate of 8m/s2 from rest until it reaches its take-off speed of 60m/s. To find the time it takes to reach this speed, we can use the equation of motion: v = u + at, where v is the final velocity, u is the initial velocity, a is the acceleration, and t is the time taken. Rearranging the equation, we have t = (v - u) / a. Plugging in the given values, t = (60 - 0) / 8 = 7.5s. Therefore, it takes 7.5 seconds for the aircraft to reach its take-off speed.

Explanation

The aircraft accelerates at a constant rate of 8m/s2 from rest until it reaches its take-off speed of 60m/s. To find the time it takes to reach this speed, we can use the equation of motion: v = u + at, where v is the final velocity, u is the initial velocity, a is the acceleration, and t is the time taken. Rearranging the equation, we have t = (v - u) / a. Plugging in the given values, t = (60 - 0) / 8 = 7.5s. Therefore, it takes 7.5 seconds for the aircraft to reach its take-off speed.

5. The key difference between velocity and speed is:-

Speed only applies to cars

Speed only applies when object move slowly.

Velocity is when the speed changes.

Velocity only applies to science experiments

Velocity is used when the direction matters.

Velocity is a measure of the speed of an object in a specific direction. Unlike speed, which only considers the magnitude of the object's movement, velocity takes into account both the speed and the direction of the object. This is important in situations where the direction of movement is relevant, such as in physics experiments or when calculating the motion of objects in a particular direction.

Explanation

Velocity is a measure of the speed of an object in a specific direction. Unlike speed, which only considers the magnitude of the object's movement, velocity takes into account both the speed and the direction of the object. This is important in situations where the direction of movement is relevant, such as in physics experiments or when calculating the motion of objects in a particular direction.

6. A cyclist accelerates from rest to 12m/s in 4s. His acceleration is:-

48m/s2

3m/s2

0.33m/s2

1.33m/s2

0.75m/s2

The cyclist accelerates from rest to a final velocity of 12 m/s in a time of 4 seconds. To find the acceleration, we can use the formula: acceleration = (final velocity - initial velocity) / time. In this case, the initial velocity is 0 m/s, the final velocity is 12 m/s, and the time is 4 seconds. Plugging these values into the formula, we get: acceleration = (12 m/s - 0 m/s) / 4 s = 12 m/s / 4 s = 3 m/s^2. Therefore, the correct answer is 3m/s^2.

Explanation

The cyclist accelerates from rest to a final velocity of 12 m/s in a time of 4 seconds. To find the acceleration, we can use the formula: acceleration = (final velocity - initial velocity) / time. In this case, the initial velocity is 0 m/s, the final velocity is 12 m/s, and the time is 4 seconds. Plugging these values into the formula, we get: acceleration = (12 m/s - 0 m/s) / 4 s = 12 m/s / 4 s = 3 m/s^2. Therefore, the correct answer is 3m/s^2.

7. A runner sprints for the line at the end of the 1500m. He is already running at 7.5m/s and he has worked out that he must be travelling at 9.3m/s in less than 9s in order to win the race. What is the smallest acceleration that will allow him to do this?

0.2m/s2

1.1m/s2

1.87m/s2

1.8m/s2

45m/s2

The runner is currently running at a speed of 7.5m/s and needs to increase his speed to 9.3m/s in less than 9 seconds. The smallest acceleration that will allow him to do this can be calculated using the formula: acceleration = (final velocity - initial velocity) / time. Plugging in the values, we get (9.3m/s - 7.5m/s) / 9s = 1.8m/s2. Therefore, the correct answer is 1.8m/s2.

Explanation

The runner is currently running at a speed of 7.5m/s and needs to increase his speed to 9.3m/s in less than 9 seconds. The smallest acceleration that will allow him to do this can be calculated using the formula: acceleration = (final velocity - initial velocity) / time. Plugging in the values, we get (9.3m/s - 7.5m/s) / 9s = 1.8m/s2. Therefore, the correct answer is 1.8m/s2.

8. To overtake a lorry while travelling at 15m/s a school minibus driver accelerates at 1.5m/s2 for 6s. What is the maximum speed the minibus achieves while overtaking?

22.5m/s

90m/s

81m/s

24m/s

32.5m/s

The minibus driver accelerates at a rate of 1.5m/s² for 6 seconds. Using the equation v = u + at, where v is the final velocity, u is the initial velocity (15m/s), a is the acceleration, and t is the time, we can calculate the final velocity. Plugging in the values, we get v = 15 + (1.5 * 6) = 15 + 9 = 24m/s. Therefore, the maximum speed the minibus achieves while overtaking is 24m/s.

Explanation

The minibus driver accelerates at a rate of 1.5m/s² for 6 seconds. Using the equation v = u + at, where v is the final velocity, u is the initial velocity (15m/s), a is the acceleration, and t is the time, we can calculate the final velocity. Plugging in the values, we get v = 15 + (1.5 * 6) = 15 + 9 = 24m/s. Therefore, the maximum speed the minibus achieves while overtaking is 24m/s.

9. A motor cyclist does an emergency stop when he is travelling at 36m/s. If the motorcycle stops in 3s what is his deceleration?

12m/s

108m/s

0.08m/s2

39m/s2

12m/s2

The deceleration of the motorcyclist can be calculated using the formula: acceleration = change in velocity / time. In this case, the change in velocity is from 36m/s to 0m/s, which is a decrease of 36m/s. The time taken for this change is 3 seconds. Therefore, the deceleration is 36m/s divided by 3s, which equals 12m/s².

Explanation

The deceleration of the motorcyclist can be calculated using the formula: acceleration = change in velocity / time. In this case, the change in velocity is from 36m/s to 0m/s, which is a decrease of 36m/s. The time taken for this change is 3 seconds. Therefore, the deceleration is 36m/s divided by 3s, which equals 12m/s².

10. A parachutist opens her parachute at an altitude of 1000m when she is travelling at 48m/s. The parachute causes her to decelerate at 4m/s2 for 8s. At what speed does she continue towards the ground?

32m/s

24m/s

12m/s

6m/s

1.5m/s

The parachutist opens her parachute when she is traveling at 48m/s. The parachute causes her to decelerate at a rate of 4m/s^2 for 8s. To find the final speed, we can use the equation v = u + at, where v is the final velocity, u is the initial velocity, a is the acceleration, and t is the time. Plugging in the values, we get v = 48 - (4 * 8) = 48 - 32 = 16m/s. Therefore, the correct answer is 16m/s.

Explanation

The parachutist opens her parachute when she is traveling at 48m/s. The parachute causes her to decelerate at a rate of 4m/s^2 for 8s. To find the final speed, we can use the equation v = u + at, where v is the final velocity, u is the initial velocity, a is the acceleration, and t is the time. Plugging in the values, we get v = 48 - (4 * 8) = 48 - 32 = 16m/s. Therefore, the correct answer is 16m/s.