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An incline problem

  • Thread starter kokok
  • Start date
  • #1
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Homework Statement


a toy cart of mass 5kg is projected up a ramp incined at 30 degree to the horizontal, with an initial velocity of 6m/s. if the frictional force opposing its motion is 4N, find the distance it travels before stopping, and its increase in gravitational potential energy at that point.


Homework Equations


F=ma
v2^2 = v1^2 + 2ad

The Attempt at a Solution


so using vector, mgsin30 - 2 = ma
24.5 = 5a
a=4.9m/s^2

sub into
v2^2 = v1^2 + 2ad
and i got 36/1.8 = 20 = d but it is very different from answer of the book
please help me to solve it
 

Answers and Replies

  • #2
hage567
Homework Helper
1,509
2

Homework Statement


a toy cart of mass 5kg is projected up a ramp incined at 30 degree to the horizontal, with an initial velocity of 6m/s. if the frictional force opposing its motion is 4N, find the distance it travels before stopping, and its increase in gravitational potential energy at that point.


Homework Equations


F=ma
v2^2 = v1^2 + 2ad

The Attempt at a Solution


so using vector, mgsin30 - 2 = ma
24.5 = 5a
a=4.9m/s^2

sub into
v2^2 = v1^2 + 2ad
and i got 36/1.8 = 20 = d but it is very different from answer of the book
please help me to solve it

Why do you have that as 2? It says the force of friction is 4 N. By the way, if the cart is being pushed up the ramp, the frictional force and the gravitational force act in the same direction. So how does that change things? Did you draw a free body diagram?
 
  • #3
Doc Al
Mentor
44,892
1,143

The Attempt at a Solution


so using vector, mgsin30 - 2 = ma
24.5 = 5a
a=4.9m/s^2
You'll need to redo this calculation. Your initial equation is not quite right. What forces act on the cart? (Include both gravity and friction.) In which direction do those forces act? What's the net force acting on the cart?
 
  • #4
10
0
oh thank you, now i get this question..what a silly mistake i made..
 
  • #5
16
0
omg. it's the same problem that I am working on right now.

but i need to solve it using the concept of conservation of energy. anyone knows how?
 
  • #6
hage567
Homework Helper
1,509
2
omg. it's the same problem that I am working on right now.

but i need to solve it using the concept of conservation of energy. anyone knows how?
What have you tried? Show some of your work.
 

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