betty weighs 420n and she is sitting on a playground swing seat that hangs 0.40m above the ground. Tom pulls the swing back and releases it, when the seat is 1.00m above the ground.
2007-01-02 05:47:09 · 3 answers · asked by Physics 101 1 in Science & Mathematics ➔ Mathematics
At the point of release
Potential energy is maximum
=mg*h
=420*.6[diffrence between 1m and .4m]
At the bottom most point
Kinetic Energy is maximum
=.5 m v^2
These have to be equated
.5*m*v^2=420*.6 [m=420/9.8]
v^2=[420*.6]/[.5*420/9.8]
=.6*9.8/.5
=11.76
v=3.429m/sec
2007-01-02 06:10:45 · answer #1 · answered by openpsychy 6 · 0⤊ 0⤋
The total energy is the sum of potential and kinetic and is conserved.
PE is mgh,
KE is mv^2/2
equate these two and solve for v.
2007-01-02 13:56:28 · answer #2 · answered by modulo_function 7 · 0⤊ 0⤋
she is at maximum speed then.
Use the conservative law of kinetic energy to calculate the speed
your teacher.
2007-01-02 13:50:24 · answer #3 · answered by gjmb1960 7 · 0⤊ 0⤋