_______________________//__/1 amu
Distance travel = 400km
Time it took to travel 400km = 5 hr
Average speed = (distance travel)/(Time for that travel)
s = 400km/5h = 80km/hr
The average speed is 80km/hr.
Answer:
a) τ = 4.47746 * 10^25 N-m
b) E = 2.06301 * 10^13 J
c) P = 3.25511*10^21 W
Explanation:
Given:
- The radius of earth r = 6.3781×10^6 m
- The angular speed of earth w = 7.27*10^-5 rad/s
- The time taken to reach above speed t = 5 yrs = 1.57784760 * 10^8 s
- The mass of earth m = 5.972 × 10^24 kg
- The inertia of sphere I = 2/5 * m* r^2
Solution:
- The angular acceleration of the earth from rest to w is given by α:
α = w / t
α = (7.27*10^-5) / (1.57784760 * 10^8)
α = 4.60754*10^-13 rad/s^2
- The required torque τ is given by:
τ = I*α
τ = 2/5 * m* r^2 * α
τ = 2/5 *(5.972 × 10^24) * (6.3781×10^6)^2 * (4.60754*10^-13)
τ = 4.47746 * 10^25 N-m
- The power required P to turn the earth to the speed w is:
P = τ*w
P = (4.47746 * 10^25)*(7.27*10^-5)
P = 3.25511*10^21 W
- The energy E required is :
E = P / t
E = (3.25511*10^21) / (1.57784760 * 10^8)
E = 2.06301 * 10^13 J
Answer:
2.4s
Explanation:
The length of the pendulum = 75ft
Diameter d = 12 inches
The time period of the pendulum is given as
T = 2pi(L/g)^1/2
Then the time it takes to move from displacement to equilibrium is given as:
t = T/4
= (Pi/2)*(L/g)^1/2
= pi/2 x [(75x0.3048)/9.81]^0.5
= 1.57x[22.86/9.81)^0.5
= 2.4s
2.4 seconds is the least amount of time that it would take.
