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  1. P

    Heat contained in the Great Lakes

    Homework Statement the largest of the Great Lakes, Lake Superior contains 1.2*10^16kg of fresh water, which has a specific capacity of 4186J/kg*C and a latent heat of fusion of 3.33*10^5J/kg. a.) If Lake Superior were still liquid at 0C, how much energy would need to be removed from the lake...
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    Momentum of pendulum after hitting it with bullet

    actually i figured it out. i was making a really stupid mistake... thanx for the help!
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    Momentum of pendulum after hitting it with bullet

    its not at the top o f its swing its at the lowest point so it will keep going.
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    Momentum of pendulum after hitting it with bullet

    well idk but my teacher said its 1.5 J.. and since its like swinging back it would be that velocity not the velocity at its lowest point.. i think
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    Momentum of pendulum after hitting it with bullet

    i thought it would be zero but than that would make the KE=0 which would not make sense
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    Momentum of pendulum after hitting it with bullet

    you cannot because you dont have the final velocity of the pendulum.
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    Momentum of pendulum after hitting it with bullet

    i see but back to the question now i feel so lost... no clue on how to solve it.
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    Momentum of pendulum after hitting it with bullet

    but i thought momentum is always conserved before and after the inelastic collision?
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    Momentum of pendulum after hitting it with bullet

    in the first one the total momentum's conserved but i would need to find the vf in order to use the equation and in the second one only total momentum is conserved the kinetic energy isnt since it would be a inelastic collision because they stick together.
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    Momentum of pendulum after hitting it with bullet

    Homework Statement An 9 g bullet is fired into a 2.5 kg pendulum bob which is initially at rest and becomes embedded in the bob. The pendulum then rises a vertical distance of 6cm. What was the initial speed of the bullet? What will be the kinetic energy of the pendulum when the pendulum...
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    Work and force

    the work done above water would be negative while the word done below water would be positive. but how can both of them have the same magnitude? that's the part i don't understand.
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    Work and force

    well when he is in water the work he does would be 1500N*5m because thats the distance he z traveling and the net force is 1500. so the work done would be 7500J. The work he does under water would not be the same as above water would it?
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    Work and force

    W=1009.5*(x+5) and W=490.5x are those two equations correct?
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    Work and force

    you cannot because you would have two unsolved, the work net and the distance.
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    Work and force

    well you dont know the distance so you cannot find the total work done.
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    Work and force

    oo it wud b fg which is 50*9.81 which is 490.5 . but that doesnt help.
  17. P

    Work and force

    Homework Statement a 50 kg diver steps off a diving board and drops straight down into the water. The water provides an upward average net force of 1500 N. If the diver comes to rest 5.0m below the water's surface, what is the total distance between the diving board and the diver's stopping...
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    Work total

    i see so the force applied would be Fgravity*sin20 which would give me 7045.96 and i would subtract the Ff to get the total force. right?
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    Work total

    Homework Statement a 2.1*10^3 kg car starts from rest at the top of a driveway that is sloped at an angle of 20 with the horizontal. An average friction force of 4.0*10^3 N impedes the car's motion so that the car's speed at the bottom of the driveway is 3.8m/s., What is the length of the...
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    Force Problem x-axis

    you have to split the 60 N into two different vector quantities since it has a horizontal and vertical magnitude. the 40 N only has a horizontal quantity. then you would add the horizontal component of 60 and 40 to get the total force in the x direction.
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    Mistake in solving for work in physics?

    the Wnet is always the same as KE?
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    Force Problem x-axis

    there are two forces acting on it so you would have to find the resultant force because you have to find the force net in order to use the F=ma equation. Finding the resultant by using vector addition method will give you the Force net and then you can plug in the mass to solve.
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    Mistake in solving for work in physics?

    Homework Statement a student wearing a frictionless in-line skates on a horizontal surface is pushed by a friend with a constant force of 45N. How far must the student be pushed, starting from rest, so that her final kinetic energy is 352J? Homework Equations The Attempt at a...
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    How long does the ball take to hit the ground?

    Homework Statement a 3 kg ball is dropped from rest from the roof on a building 176.4 m high. While the ball is falling, a horizontal wind exerts a constant force of 12 N on the ball? Part 1) How long does the ball take to hit the ground? Part 2) How far from the building does the ball hit the...
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    Force q.

    oo i seee thanx alot for the help!
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    Force q.

    but it doesnt talk about ropes in the problem? coz i thought you only use tension when there is pulleys.
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    Force q.

    ooo yup ur right. could you explain what exactly is tension? because in my book when they say like #N is needed to set something in motion the example in the book used that as Fsmax.
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    Force q.

    Homework Statement a 5.1*10^2 kg bundle of bricks is pulled up a ramp at an incline of 14 degrees to a construction site. the force needed to move the bricks up the ramp is 4.1*10^3 N. What is the coefficient of static fiction between the bricks and the ramp? Homework Equations well...
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