Answer: A-they change the direction of the forces
Explanation:
Any device which makes our work simpler is known as a machine. A machine may increase the amount of output force which is determined by its mechanical advantage or a machine changes the direction of the force.
In the given situation the input force acts in the downward direction to pull the rope. The output force acts on the flag being pulled upwards at the other end. Thus, the direction of the forces varies. Correct option is A.
Answer:
85.8 m/s
Explanation:
We know that the length of the circular path, L the plane travels is
L = rθ where r = radius of path and θ = angle covered
Now,its speed , v = dL/dt = drθ/dt = rdθ/dt + θdr/dt
where dθ/dt = ω = angular speed = v'/r where v' = maximum speed of plane and r = radius of circular path
Now, from θ = θ₀ + ωt where θ₀ = 0 rad, ω = angular speed and t = time,
θ = θ₀ + ωt = 0 + ωt = ωt
So, v = rdθ/dt + θdr/dt
v = rω + ωtdr/dt
v = (r + tdr/dt)ω
v = (r + tdr/dt)v'/r
v = v' + tv'/r(dr/dt)
v = v'[1 + t(dr/dt)/r]
Given that v' = 110 m/s, t = 33.0s, r = 120 m and dr/dt = rate at which line is shortened = -0.80 m/s (negative since it is decreasing)
So, v = 110 m/s[1 + 33.0 s(-0.80 m/s)/120 m]
v = 110 m/s[1 + 11.0 s(-0.80 m/s)/40 m]
v = 110 m/s[1 + 11.0 s(-0.02/s)]
v = 110 m/s[1 - 0.22]
v = 110 m/s(0.78)
v = 85.8 m/s
(a) The work done by the person is 18.83465 kJ.
(b) The average power performed by the person during the walk is 51.4 W.
(c) The amount of food calories burnt is 4.5 Cal.
<h3>Work done by the person</h3>
The work done by the person is calculated as follows;
W = Fd
W = mgh
W = (89.2 x 9.8) x (0.162 x 133)
W = 18,834.65 J
W = 18.83465 kJ
<h3>Average power of the person</h3>
P = Fv
where;
v = (d)/t
v = (133 x 0.162)/(6 x 60 + 6)
v = (133 x 0.162)/(366)
v = 0.0588 m/s
P = (89.2 x 9.8) x 0.0588
P = 51.4 W
<h3>Amount of food calories burnt</h3>
4.1868 kJ = 1 Cal
18.83465 kJ = ?
= 4.5 Cal
Learn more about work done here: brainly.com/question/8119756
#SPJ1
Answer: 3.27kg
Explanation:
Inertia can be said to be the resistance of an object to a change in its motion. This includes a change in its direction. An object will stay still or keep moving at the same speed and in a straight line, except it is acted upon by an unbalanced external force.
Given F = 30N
r = 0.14m
a = 130rad/s²
Then, T = Fr
T = 30*0.14
T = 4.2Nm
Also, T = inertia * acceleration
Inertia = 4.2/a
Inertia = 4.2/130
Inertia = 0.032
Also, inertia = mr²/2
0.032 = m * (0.14²)/2
0.032 = m * 0.0098
m = 0.032/0.0098
m = 3.27kg
Answer:
y = 150 Km
Explanation:
given,
Distance of the planet Mars from earth D = 2.11 × 10¹¹ m
The diameter of the telescope's objective lens d = 0.949 m
The wavelength of light λ = 553 nm
= 553 x 10⁻⁹ m
resolution of the telescope = ?
y = 150003 m
y = 150 Km
the minimum feature size is equal to y = 150 Km
