Question

# Naas notes the speedometer readings of his friend’s car the moment he started applying brakes until the car stopped. Later, he calculated the acceleration of the car and found it out to be ___.

- Negative
- Positive
- Zero
- None of the above

Hint:

### Acceleration is the rate of change of velocity.

## The correct answer is: Negative

### The direction of the acceleration is opposite to the direction of velocity as the speed of car is slowing down, then the acceleration will be negative.

Negative acceleration is also known as deceleration.

### Related Questions to study

### A car moving at a velocity of 76 m/s decreases its velocity uniformly to 6 m/s in 10 s. Work out its acceleration with a proper sign.

Negative acceleration is also known as deceleration.

### A car moving at a velocity of 76 m/s decreases its velocity uniformly to 6 m/s in 10 s. Work out its acceleration with a proper sign.

Negative acceleration is also known as deceleration.

### A car moving at a velocity of 5 m/s increases its velocity uniformly to 50 m/s in 10 s. Work out its acceleration with a proper sign.

When there is a speeding of an object the the acceleration will be positive.

### A car moving at a velocity of 5 m/s increases its velocity uniformly to 50 m/s in 10 s. Work out its acceleration with a proper sign.

When there is a speeding of an object the the acceleration will be positive.

### Which of the following is/are true about the attributes of a uniform circular motion?

a. The velocity points in a tangential direction at every point of motion.

b. The speed changes throughout the motion of the body.

c. The acceleration being perpendicular to the velocity points towards the center.

### Which of the following is/are true about the attributes of a uniform circular motion?

a. The velocity points in a tangential direction at every point of motion.

b. The speed changes throughout the motion of the body.

c. The acceleration being perpendicular to the velocity points towards the center.

### Pick the odd one out.

Acceleration is rate of change of velocity.

### Pick the odd one out.

Acceleration is rate of change of velocity.

### Match the following and choose the option with all the right matches:

i |
Positive acceleration |
a |
Slowing down |

ii |
Negative acceleration |
b |
Uniform motion |

iii |
Zero acceleration |
c |
The motion of a running athlete |

iv |
Non-uniform acceleration |
d |
Speeding up |

Acceleration is a vector quantity

### Match the following and choose the option with all the right matches:

i |
Positive acceleration |
a |
Slowing down |

ii |
Negative acceleration |
b |
Uniform motion |

iii |
Zero acceleration |
c |
The motion of a running athlete |

iv |
Non-uniform acceleration |
d |
Speeding up |

Acceleration is a vector quantity

### A train starts from rest and picks up a velocity of 15 m/s in 3 s. The acceleration of the train is ___ m/s^{2}.

### A train starts from rest and picks up a velocity of 15 m/s in 3 s. The acceleration of the train is ___ m/s^{2}.

### Which of the following constantly changes during a uniform circular motion?

When an object completes one round then the displacement will be zero.

### Which of the following constantly changes during a uniform circular motion?

When an object completes one round then the displacement will be zero.

### Sam wants to modify the formula for acceleration

I.e., a = (v – u)/ t

Where v = final velocity, u = initial velocity, t= time, a = acceleration, to suit the special case of freefall of a ball dropped from the top of a building. He chooses to make the following substitutions in the formula.

a. v= 0

b. u= 0

c. a= 9.8 m/s^{2}

Identify the correct substitutions.

Acceleration of gravity is 9.8ms^{-2}

### Sam wants to modify the formula for acceleration

I.e., a = (v – u)/ t

Where v = final velocity, u = initial velocity, t= time, a = acceleration, to suit the special case of freefall of a ball dropped from the top of a building. He chooses to make the following substitutions in the formula.

a. v= 0

b. u= 0

c. a= 9.8 m/s^{2}

Identify the correct substitutions.

Acceleration of gravity is 9.8ms^{-2}

### A monkey falls from the top of a tall tree reaches a velocity of ___ m/s in 20 s.

### A monkey falls from the top of a tall tree reaches a velocity of ___ m/s in 20 s.

### A body moves in such a way that its velocity increases by 4 m/s every second. Its acceleration is ___ m/s^{2}.

### A body moves in such a way that its velocity increases by 4 m/s every second. Its acceleration is ___ m/s^{2}.

### What is the acceleration of a truck which starts from rest, and after 5 s its velocity is 20 m/s? What is the direction of the acceleration of the truck?

### What is the acceleration of a truck which starts from rest, and after 5 s its velocity is 20 m/s? What is the direction of the acceleration of the truck?

### Acceleration is a _____ quantity, as it has ____.

In positive acceleration its magnitude will be positive and direction is same as of the velocity.

In negative acceleration its magnitude will be negative and direction is opposite as of the velocity.

### Acceleration is a _____ quantity, as it has ____.

In positive acceleration its magnitude will be positive and direction is same as of the velocity.

In negative acceleration its magnitude will be negative and direction is opposite as of the velocity.

### A car moves at a speed of 5 m/s throughout its journey. What is its acceleration?

the car is not speeding up or slowing down.

### A car moves at a speed of 5 m/s throughout its journey. What is its acceleration?

the car is not speeding up or slowing down.

### A car moving at a velocity of 6.5 m/s increases its velocity uniformly to 78 m/s in 10 s. Work out its acceleration with a proper sign.

Positive acceleration means the direction of acceleration is same as of the direction of velocity.

### A car moving at a velocity of 6.5 m/s increases its velocity uniformly to 78 m/s in 10 s. Work out its acceleration with a proper sign.

Positive acceleration means the direction of acceleration is same as of the direction of velocity.