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ruby1
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Hi there, I have a physics test tomorrow and I've been trying to review and practice some problems, but I'm not sure I'm understanding it. When the teacher goes through the questions it makes sense, but I'm not always sure where to start. I have a couple questions that I don't understand, even if I could understand one of them it would be good.
What is the average force exerted by a shot-putter on a 7.0 kg shot if the shot is moved through a distance of 2.8m and is released with a speed of 13 m/s?
So I know
m=7.0 kg
v=13 m/s
d=2.8m
g=9.8 N/kg or 9.8 m/s
and I'm trying to find force.
a=v/t
F=ma
Not really sure which equations to use.
I'm not sure if the distance is even relevant, does it help with the problem at all?
The first thing I thought to do was find the acceleration using a=v/t and then using F=ma, but I don't know the time and wouldn't the acceleration be 0? So if a=o, then F=ma would also be 0, and that doesn't make sense. Overall I'm just not too sure where I would start if I was given a question like this on the test.
The book says the answer is 2.1 x 10N.
A 6500 kg helicopter accelerates upwards at 0.60 m/s while lifting a 1200 kg car. a) What is the lift force exerted by the air on the rotors? b) What is the tension in the cable (ignore its mass) that connects the car to the helicopter?
total mass=7700kg
a=0.60m
So for a) I tried to do F=ma
F= (7700kg) (0.60m) = 4620 N
But the book says the answer is 8.01 x 10[tex]^{}4[/tex]N.
and for b) i honestly have no idea where to start, but the answer is 1.25 x 10[tex]^{}4[/tex]N.
I would really appreciate it if anyone could help me with these problems, thank you very much!
Homework Statement
What is the average force exerted by a shot-putter on a 7.0 kg shot if the shot is moved through a distance of 2.8m and is released with a speed of 13 m/s?
So I know
m=7.0 kg
v=13 m/s
d=2.8m
g=9.8 N/kg or 9.8 m/s
and I'm trying to find force.
Homework Equations
a=v/t
F=ma
Not really sure which equations to use.
The Attempt at a Solution
I'm not sure if the distance is even relevant, does it help with the problem at all?
The first thing I thought to do was find the acceleration using a=v/t and then using F=ma, but I don't know the time and wouldn't the acceleration be 0? So if a=o, then F=ma would also be 0, and that doesn't make sense. Overall I'm just not too sure where I would start if I was given a question like this on the test.
The book says the answer is 2.1 x 10N.
Homework Statement
A 6500 kg helicopter accelerates upwards at 0.60 m/s while lifting a 1200 kg car. a) What is the lift force exerted by the air on the rotors? b) What is the tension in the cable (ignore its mass) that connects the car to the helicopter?
total mass=7700kg
a=0.60m
The Attempt at a Solution
So for a) I tried to do F=ma
F= (7700kg) (0.60m) = 4620 N
But the book says the answer is 8.01 x 10[tex]^{}4[/tex]N.
and for b) i honestly have no idea where to start, but the answer is 1.25 x 10[tex]^{}4[/tex]N.
I would really appreciate it if anyone could help me with these problems, thank you very much!