Answer:
1.28 m
Explanation:
Given;
Radius, r = 1.5 cm = 0.015 m
Time, t = 19 s
Average angular speed = 4.5 rad/s
Consider a point when the tape is moving at a constant velocity along the circumference of the circular reel of radius r. The linear velocity v at this point is given by;
v = rω ----(1)
Where
v is the linear velocity of the circular motion
r is the radius of the reel
ω is the the angular velocity.
At a point the tap undergoes a linear motion before passing round the reel of the cassette. The linear velocity v at this point is given by;
v = L/t ----(2)
where;
v is the velocity of the linear motion
L is the length of the tape (distance covered by the tape)
t is the time taken
Equating equation(1) and equation (2)
L/t = rω
L = rωt
Substituting the given values,
L = 0.015 × 4.5 × 19
L = 1.2825 m
L = 1.28 m
Answer:
a) 2.02 years
b) 8.1 x 10⁻⁸.
Explanation:
Time period of a rotating body T² is proportional to radius of orbit R³ So
T₁² / T₂² = R₁³ /R₂³ ( T₁ and R₁ is time period and radius of orbit of the earth .)
1² / T₂² =( 1/1.6)³
T₂ = 2.02 years.
Kinetic energy of an orbiting body = 1/2 m v₀² ( v₀ is orbital speed)
= 1/2 m x 2 g R = m x G m/R² X R= m² x G /R
Kinetic energy of asteroid K₁ / kinetic energy of earth K₂ =
(mass of asteroid/mass of earth)² x( radius of earth / radius of asteroid)
=( 3.6 x 10⁻⁴)² x 1/1.6 = 8.1 x 10⁻⁸ .
It goes in the downward direction
Venus has the slowest rotation rate.
It takes Venus 243.7 Earth days to rotate once.
Planet Period
Venus 243.7 (Earth) days
Mercury 58.8 days
Pluto 6.4 days
Mars 24.6 hours
Earth 23.9 hours
Uranus 17.2 hours
Neptune 16.1 hours
Saturn 10.7 hours
Jupiter 9.9 hours
Interesting . . . the largest planet rotates the fastest.
I wonder why that is.
