Answer:
18.84 ft
Step-by-step explanation:
¼×2×3.14×12 = 18.84 ft
Let the height of the rectangle = h
2b + 2h = 100
2(38) + 2h = 100
2h = 100 - 76
h = 12mm
area of rectangle = base x height
= 38 x 12
= 456mm²
Answer:
Rolling case achieves greater height than sliding case
Step-by-step explanation:
For sliding ball:
- When balls slides up the ramp the kinetic energy is converted to gravitational potential energy.
- We have frictionless ramp, hence no loss due to friction.So the entire kinetic energy is converted into potential energy.
- The ball slides it only has translational kinetic energy as follows:
ΔK.E = ΔP.E
0.5*m*v^2 = m*g*h
h = 0.5v^2 / g
For rolling ball:
- Its the same as the previous case but only difference is that there are two forms of kinetic energy translational and rotational. Thus the energy balance is:
ΔK.E = ΔP.E
0.5*m*v^2 + 0.5*I*w^2 = m*g*h
- Where I: moment of inertia of spherical ball = 2/5 *m*r^2
w: Angular speed = v / r
0.5*m*v^2 + 0.2*m*v^2 = m*g*h
0.7v^2 = g*h
h = 0.7v^2 / g
- From both results we see that 0.7v^2/g for rolling case is greater than 0.5v^2/g sliding case.
An = a1 * r^(n-1)
n = term to find = 18
a1 = first term = 3
r = common ratio = 4/3
now we sub
a18 = 3 * 4/3^(18 - 1)
a18 = 3 * 4/3^17
a18 = 3 * 133
a18 = 399
