Thursday

April 24, 2014

April 24, 2014

Posted by **John** on Tuesday, January 21, 2014 at 3:05pm.

- Physics -
**Damon**, Tuesday, January 21, 2014 at 3:33pmI assume that Theta is up and down from horizontal

calling theta = A

d sin A /dA = cos A

d sin A/dt = d sin A/dA * dA/dt

so

d sin A /dt = cos A (dA/dt )

similarly

d cos A/dt = -sin A dA/dt

That settled, let's look at the problem

Force = m * a

a = F/7

da/dt = (1/7) dF/dt

F in direction of motion = 20 cos A

d F/dt =20 d/dt(cosA)

but we already know what that is

dF/dt = 20 (-sin A) dA/dt

A = 28 deg = .489 radian

sin A = .469

dA/dt = 3*10^-2 (pi/180) = 5.24*10^-5 rads/s

so

dF/dt = 20 (-.489)(5.24*10^-5)

da/dt =(1/7)dF/dt = (20/7)(-.489)(5.24*10^-5)

- Physics -
**bobpursley**, Tuesday, January 21, 2014 at 3:34pmNet force=mass*acceleration

20*cosTheta=mass* acceleratin

take the deriviative...

-20SinTheta dTheta/dt=mass*d(acceleration)/dt

yes, dTheta/dt is in radians/sec, so convert it. solve for d(acceleration)/dt and the units will be m/sec^3

**Related Questions**

physics - A 3.24 kg block located on a horizontal frictionless floor is pulled ...

physics - I am trying to study for my exam i have tomorrow and this type of ...

Physics - A block of mass 7.5 kg is pulled along a horizontal frictionless floor...

physics - A 5 kg block is pulled along a horizontal frictionless floor by a ...

physics - A 3.5 kg block, initially in motion, is pushed along a horizontal ...

- A 3.5 kg block, initially in motion, is pushed along a horizontal floor by a...

physics - A 3.24 kg block located on a horizontal frictionless floor is pulled ...

physics - A 20.0 kg block is connected to a 30.0 kg block by a string that ...

ph - A 20.0 kg block is connected to a 30.0 kg block by a string that passes ...

Physics - A 20.0 kg block is connected to a 30.0 kg block by a string that ...