Forces and constant velocity

In summary, a car with constant velocity hits a block with a mass of 300kg and maintains its speed while pushing the block until it runs out of fuel. The force applied on the block can be found using the equation F=ma, where a=0 since the velocity is constant. The coefficient of friction between the block and surface is 0.22, and the friction force is equal to the applied force. Once constant velocity is attained, the net force on the block is zero.
  • #1
macmac410
9
0

Homework Statement


a car with a constant velocity of 1m/s, accidentally hits a huge block with a mass of 300kg. Instead of stopping the driver constantly maintain the speed, pushing the block along the way until the car runs out of fuel. Find the force applied in the block
if the coefficient of friction in the block and surface is 0.22.

Homework Equations


f=ma


m=300kg
a=0 since velocity is constant

u=Ff/Fn
Fn=W=mg

u=Ff/mg
Ff=u(mg)


The Attempt at a Solution


i don't know where to start but it seems that the forced applied on the block was zero since velocity is constant? Am i riGht?
 
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  • #2
macmac410 said:
i don't know where to start but it seems that the forced applied on the block was zero since velocity is constant? Am i riGht?
No. Since the velocity is constant the net force on the block must be zero, not the applied force. What force acts on the block opposing the applied force?
 
  • #3
Doc Al said:
No. Since the velocity is constant the net force on the block must be zero, not the applied force. What force acts on the block opposing the applied force?

friction acts on the block opposing the applied force,
since you said that the net force must be zero hence!
Ffriction=Fapplied?

thanks now its getting clearer,
but how is it happened that frictional force is equal to applied force? If the two force are equal then there must be no motion on them?
 
  • #4
macmac410 said:
friction acts on the block opposing the applied force,
since you said that the net force must be zero hence!
Ffriction=Fapplied?
Right. (Now you've got to figure out the friction force.)

thanks now its getting clearer,
but how is it happened that frictional force is equal to applied force? If the two force are equal then there must be no motion on them?
No, it means that the block isn't changing its velocity (once it's moving along with the car, that is). I presume that they want the applied force once constant velocity is attained.
 
  • #5
Thank you very much Doc Al!
now i can find the right answer..
 
Last edited:

1. What is a force?

A force is a push or pull that can cause an object to accelerate or change its direction of motion. It is measured in units of Newtons (N). Some common types of forces include gravity, friction, and applied forces from contact with other objects.

2. How is force related to constant velocity?

According to Newton's First Law of Motion, an object in motion will continue to move at a constant velocity unless acted upon by an unbalanced force. This means that if the net force on an object is zero, it will maintain a constant velocity. In other words, forces can either cause an object to speed up, slow down, or change direction.

3. What is the difference between constant velocity and constant speed?

Constant velocity refers to an object moving at a steady rate in a specific direction, while constant speed refers to an object moving at a steady rate regardless of direction. In other words, an object can have a constant velocity if it is moving in a straight line at a steady speed, but it cannot have a constant speed if it is changing direction.

4. How do forces affect objects with different masses?

According to Newton's Second Law of Motion, 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 same force will cause a larger acceleration on an object with a smaller mass compared to an object with a larger mass.

5. Can an object have constant velocity while experiencing a force?

Yes, an object can have a constant velocity while experiencing a force if the force is balanced by an equal and opposite force. This is known as an equilibrium condition, where the net force on an object is zero, resulting in no change in velocity. However, if the forces are unbalanced, the object will accelerate in the direction of the greater force.

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