Homework Statement
A 3.10 kg, 31.0-cm-diameter disk in the figure is spinning at 300 rpm, how much force must a brake apply that is perpendicular to the rim of the disk to bring the disc to a halt in 2.4 s.Homework Equations
t=i*alpha wf=0+alpha*t t=fr*sin(theta)The Attempt at a Solution...
Ok you can't set h=dsin(theta) that gives you the wrong answer as i get about 140 cm. I did the math for the cube without friction and it moves about 50 cm, so if there was friction it would obviously be less than 50 cm.
Is the potential energy equation technically invalid as potential energy is defined as mgh but as h changes g changes, so if i launched a projectile at 2000 m/s straight up or 90 degrees, how high would it go. Guess the change in g is negligible at heights below 1000m. So technically the exact...
How does the acceleration due to gravity change as you go underneath the earth, someone told me that it increases then decreases as you approach the core, so theoretically the acceleration due to gravity at the center of the Earth or the inner core is zero? So would you be weightless at the...
There's the x component of gravity and the normal force, but I'm not sure the x component of gravity does work. I know with respect to the cube the y component of gravity gives it potential energy. Does the spring do work tho, as it does apply a force f=-kx over a distance of 10 cm, that energy...
Homework Statement
A 50 g plastic cube slides up and down a 30 degree slope with friction. The plastic cube is pressed against a spring at the bottom of the slope, compressing the spring 10 cm. The spring constant is 25 N/m. When the plastic cube is released, what total distance will it travel...
Guess it will be negative in my case cause up is positive and down is negative and it's pulling down. But what is really important during 2 dimensional motion is if the velocity vector is in the same direction as gravity then gravity is positive, if the velocity vector is in the opposite...
If a ball is thrown up while it's going up gravity is negative but when it's going down it's positive, so it can be either positive or negative right? But what also confuses me as when it's is seen as negative i see it as decelerating an object when it's supposed to accelerate it.
Yes i live in the us don't won't to learn the imperial system just curious as i was confused about that part. So what's the difference between a poundal and lbf
I know that purely the acceleration due to gravity is positive because it accelerates things not decelerates or negative acceleration. But in some cases it can be negative but I'm not sure in which cases. For example if I'm just standing here on the ground is gravity working in a positive or...