Answer:
I =1.8 kgm^2
Explanation:
In order to calculate the moment of inertia of the door you use the following formula, which relates the torque applied to the door with its moment of inertia and angular acceleration:
(1)
τ: torque applied to the door
I: moment of inertia of the door
α: angular acceleration = 5 rad/s^2
The torque is also given by τ = Fd, where F is the force applied at a distance of d to the pivot of the door (hinge axis).
F = 10 N
d = 0.9 m
You replace the expression for τ, and solve for I:
The moment of inertia of the door is 1.8 kgm^2
Because they're quadcopters
Hello!
The balloon explodes, because the pressure builds up inside and the air want to expand. Letter a)
Hugs!
Answer:
3.84 erg
Explanation:
According to Hooke's law, the energy required to stretch a spring by x length is
where k is the spring constant. We can plug in E = 4 and x = 10 to estimate k
To stretch 4cm further (at 14cm), the total work required is
The additional work needed is 7.84 - 4 = 3.84 erg
Vertically we can say
<span>Vertical acceleration = - g </span>
<span>Vertical velocity = u sinѲ - gt [Ѳ = 42; u = 12 m/s] </span>
<span>Vertical displacement = u sinѲt - (1/2) g t^2 + 9.5 </span>
<span>When the rock hits the ground, its vertical displacement will be zero. So we can say.. </span>
<span>u sinѲt - (1/2) g t^2 + 9.5 = 0 </span>
<span>I'll rearrange this .... </span>
<span>- (1/2) g t^2 + u sinѲt + 9.5 = 0 </span>
<span>Can you see that we now have a quadratic in t? </span>
<span>Using the well known formula </span>
<span>t = [ - u sinѲ ± √( u^2 sin^2Ѳ - 4(( - (1/2)g * 9.5))] / (- g) </span>
<span>t = [- u sinѲ ± √( u^2 sin^2Ѳ + 19g)] / (-g) </span>
<span>t = [- 8.03 ± √(250.86)] / (-9.81) </span>
<span>t = [- 8.03 ± 15.84] / (-9.81) </span>
<span>t = (- 8.03 + 15.84) / (-9.81) or t = (-8.03 - 15.84) / (-9.81) </span>
<span>t = - 0.8 or t = 2.43 </span>
<span>Well, a negative time has no meaning so </span>
<span>t = 2.43 seconds. </span>