- #1
LostShadow
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Hello. Got a few simple physics problems.
Cannon fires a ball at 30 degrees to the horizontal at a speed of 50 m/s. The cannon is 10 m above the ground. What is the ball's speed when it eventually falls to the ground, using energy conservation! That really threw me off.
t = square root of ( 2 times distance / 9.8 m/s^2 )
= square root of ( 2(10 m) / 9.8 m/s^2 )
= 1.42 s
d = 50 m/s (1.42) = 71 m in the horizontal
So I know v = at, but I don't know the use "energy of conservation" thing.
A .1 kg ball is at the end of 1.0 m string. It is swung in a verticle circle whose center is 2.0 m above floor. When the string is horizontal and the ball is moving upward, the string suddenly breaks, and the ball reaches a height of 5.0 m. What was the tension in the string the instant it broke?
Tension = N - mg that I know of.
From what I know, tension is another cute word for force, right, like T = ma<something theta>, where something = {sine, cosine, etc. }
Is this an L = mvr kind of problem? I have the mass of ball, velocity of ball, and radius of circle, but don't know how to convert it to tension.
And I have another question.
Suppose I have something like.
____|____
|________|
____|____
|________|
Where | is a string, and the 2 blocks are accelerating upward at 5 m/s^2.
How do I find the tension at the top of the rope? The blocks are 2.0 kg each, and the rope is .5 kg.
The force = sum of blocks and rope * acceleration.
If the whole thing is going upward, do I still take into consideration the 9.8 m/s^2?
Homework Statement
Cannon fires a ball at 30 degrees to the horizontal at a speed of 50 m/s. The cannon is 10 m above the ground. What is the ball's speed when it eventually falls to the ground, using energy conservation! That really threw me off.
Homework Equations
t = square root of ( 2 times distance / 9.8 m/s^2 )
= square root of ( 2(10 m) / 9.8 m/s^2 )
= 1.42 s
d = 50 m/s (1.42) = 71 m in the horizontal
The Attempt at a Solution
So I know v = at, but I don't know the use "energy of conservation" thing.
Homework Statement
A .1 kg ball is at the end of 1.0 m string. It is swung in a verticle circle whose center is 2.0 m above floor. When the string is horizontal and the ball is moving upward, the string suddenly breaks, and the ball reaches a height of 5.0 m. What was the tension in the string the instant it broke?
Homework Equations
Tension = N - mg that I know of.
From what I know, tension is another cute word for force, right, like T = ma<something theta>, where something = {sine, cosine, etc. }
The Attempt at a Solution
Is this an L = mvr kind of problem? I have the mass of ball, velocity of ball, and radius of circle, but don't know how to convert it to tension.
And I have another question.
Suppose I have something like.
____|____
|________|
____|____
|________|
Where | is a string, and the 2 blocks are accelerating upward at 5 m/s^2.
How do I find the tension at the top of the rope? The blocks are 2.0 kg each, and the rope is .5 kg.
The force = sum of blocks and rope * acceleration.
If the whole thing is going upward, do I still take into consideration the 9.8 m/s^2?