Finding the velocity of an inclined mass

In summary, the mass of a car sliding down an incline at a 60 degree angle with a kinetic fraction coefficient of 0.1 and starting from rest will have a velocity of 40m/s after 5 seconds.
  • #1
10
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Homework Statement


As shown in the figure, ( a mass sliding down an incline of 60°) a car of 1000 kg mass start from the rest, it's velocity after 5s is? ( the kinetic fraction coefficient 0.1)

Homework Equations


E1=E2
K1+U1=K2+U2
E1+Wf=E2

The Attempt at a Solution


-Fk= mg cos 60 (0.1) = -490
K1+U1 + Wf = K2 + U2
We should cancel K1 and U2 because they equal zero
Then
Mgh -Fk d = 1/2 mv^2
Cancelling both m from each side
gh -Fk (vt) = 1/2 v^2
9.8*h+490(5v) = 1/2 v^2

Then I don't know what to do
 
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  • #2
Since you want the speed at a given time, why not find the acceleration and then use kinematics. Start with Newton's 2nd law.
 
  • #3
Doc Al said:
Since you want the speed at a given time, why not find the acceleration and then use kinematics. Start with Newton's 2nd law.

I was doing the wrong law for this equation.

mg sin 60 - Fk = ma
1000*9.8*sin60 - ( 0.1 * 1000*9.8*cos60)= 1000a

8487.07-490=1000a
7997.04/1000
= 40m/s
 
  • #4
Sall1230 said:
I was doing the wrong law for this equation.

mg sin 60 - Fk = ma
1000*9.8*sin60 - ( 0.1 * 1000*9.8*cos60)= 1000a

8487.07-490=1000a
7997.04/1000
= 40m/s
Good.
 

What is the formula for finding the velocity of an inclined mass?

The formula for finding the velocity of an inclined mass is v = √(2ghsinθ), where v is the velocity, g is the acceleration due to gravity, h is the height of the incline, and θ is the angle of the incline.

Can the velocity of an inclined mass be negative?

Yes, the velocity of an inclined mass can be negative if the mass is moving downwards along the incline. In this case, the negative sign indicates that the velocity is in the opposite direction of the motion.

How does the angle of the incline affect the velocity of the mass?

The angle of the incline affects the velocity of the mass by changing the value of the sine function in the velocity formula. As the angle increases, the value of the sine function also increases, resulting in a higher velocity.

What is the unit of measurement for velocity?

The unit of measurement for velocity is meters per second (m/s). This indicates the distance traveled in meters divided by the time taken in seconds.

What are some real-life applications of finding the velocity of an inclined mass?

Some real-life applications of finding the velocity of an inclined mass include calculating the speed of a rollercoaster on an inclined track, determining the velocity of a skier going down a slope, and finding the speed of a car driving up or down a hill.

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