Newtons 2nd Law - Kinematic

In summary, Newton's 2nd Law of Motion states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. This law is related to kinematics, as it helps us understand why objects move in a certain way. An example of this law in action is when pushing a heavy box and a light box with the same amount of force, the heavier box will have a slower acceleration due to its greater mass. The direction of the force also affects an object's acceleration, with a force in the same direction as the object's motion resulting in acceleration, and a force in the opposite direction resulting in deceleration. This law can be applied to both linear and rotational motion, with
  • #1
tennisacerg
4
0
Can you please help me out with this problem?!?

Suppose that a 1000 kg car is traveling at 25 m/s (about 55 mph). It brakes can apply a force of 5000 N. What is the minimum distance required for the car to stop.

:confused:
 
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  • #2
acceleration=f/m
that's negative 5m/(ss)
Now the kinematics are easy--but ask if you need help.

Another approach is energy. Work to stop the car=car's kinetic energy=
(.5)(mass)(velocity squared)= (distance)(force by brakes)
 
  • #3


According to Newton's 2nd Law, the acceleration of an object is directly proportional to the net force applied to it and inversely proportional to its mass. In this case, the net force acting on the car is the force of friction between the brakes and the wheels, which is equal to the force applied by the brakes (5000 N). We can use the equation F=ma to calculate the acceleration of the car, which is equal to 5000 N / 1000 kg = 5 m/s^2.

Now, using the kinematic equation vf^2 = vi^2 + 2ad, where vf is the final velocity (which is 0 m/s since the car is stopping), vi is the initial velocity (25 m/s), a is the acceleration (5 m/s^2), and d is the distance required to stop, we can rearrange the equation to solve for d.

d = (vf^2 - vi^2) / 2a

Substituting in the values, we get:

d = (0 - 25^2) / 2(5) = 312.5 m

Therefore, the minimum distance required for the car to stop is 312.5 meters. Keep in mind that this is assuming ideal conditions and does not take into account factors such as reaction time and road conditions.
 

1. What is Newton's 2nd Law of Motion?

Newton's 2nd Law of Motion states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. This means that the greater the force applied to an object, the greater its acceleration will be, and the more massive the object is, the slower its acceleration will be.

2. How is Newton's 2nd Law related to kinematics?

Kinematics is the study of motion, and Newton's 2nd Law is a fundamental law of physics that describes the relationship between force, mass, and acceleration. Kinematics helps us understand how objects move, and Newton's 2nd Law tells us why objects move in a certain way.

3. Can you give an example of Newton's 2nd Law in action?

Imagine pushing a heavy box and a light box with the same amount of force. The heavier box will have a slower acceleration because it has more mass, while the lighter box will have a faster acceleration. This is an example of Newton's 2nd Law, as the force (pushing) is the same for both objects, but the acceleration is different due to their different masses.

4. How does the direction of the force affect an object's acceleration according to Newton's 2nd Law?

The direction of the force affects an object's acceleration by changing its velocity. If the force is applied in the same direction as the object's motion, the object will accelerate in that direction. However, if the force is applied in the opposite direction, the object will decelerate or slow down in that direction.

5. Can Newton's 2nd Law be applied to both linear and rotational motion?

Yes, Newton's 2nd Law can be applied to both linear and rotational motion. In linear motion, the force and acceleration are in the same direction, while in rotational motion, the force and acceleration act perpendicular to each other. However, the same principle applies, where a greater force will result in a greater acceleration, and a greater mass will result in a slower acceleration.

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