A car of mass 100kg is moving with a certain velocity it brought to rest by the application of brakes within a distance of 10m when the average resistance being to it is 250N what was the velocity of the motor car
Answers
Explanation:
Newton’s Laws
In 1687, Isaac Newton created three laws of motion to describe the relationship between a body and the forces acting upon it, and how the body moves in response to those forces.
Part of
Physics (Single Science)
Forces, space and radioactivity
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Newton’s Second Law
Unbalanced forces
When the forces acting on an object do not balance, the resultant force will cause the object to accelerate in the direction of the resultant force.
In other words, a resultant force on a body will cause it to change its velocity. This simply means that unbalanced forces will cause:
acceleration
deceleration
change in direction
A resultant force is the leftover or net force when all the forces acting on the object have been combined.
The relationship between the resultant force, the mass of the object and the object’s acceleration is:


You will have to be able to state this equation in the examination.
Question
A car weighs 1,000 kg. The resultant force is 5,000 N. Use the Fma triangle to find the acceleration of the car.
Reveal answer
Resultant force and calculating acceleration

To calculate the acceleration, you must find the resultant force so that you can divide it with the car's mass.
The resultant force = 4,000 N - 1,000 N = 3,000 N

= 3,000 N ÷ 1,000 kg
= 3 m/s2
The first car accelerates because the car is moving in the same direction as the resultant force. Now look at the second car.

Resultant force = -7,000 N

= -7,000 N ÷ 1,000 kg
= -7 m/s2
The second car decelerates. It is moving in the opposite direction to the resultant force.
Acceleration and mass are inversely proportional. This means that if the mass of the vehicle doubles, the acceleration halves if the resultant force doesn’t change.
Resultant force and acceleration are directly proportional. If the resultant force doubles, the acceleration of the vehicle also doubles if the mass of the vehicle is the same.
Question
A car has a mass of 1,200 kg, and an engine that can deliver a force of 6,000 N. Find the acceleration of the car.
Reveal answer
Question
Find the force developed by a speed boat engine, if the boat has a mass of 300 kg and can accelerate at a rate of 1.5 m/s2.
Reveal answer
Question
In a theme park, one of the rides has a motor that can deliver a force of 3,600 N to an empty passenger car, causing it to accelerate at 4.5 m/s2.
Find the mass of the car.
Reveal answer
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Glossary
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