Answer:
a)
840 N
b)
10920 J
c)
- 10192 J
d)
4.3 m/s
Explanation:
a)
T = tension force in the cable in upward direction = ?
a = acceleration of the person in upward direction = 0.70 m/s²
m = mass of the person being lifted = 80 kg
Force equation for the motion of person in upward direction is given as
T - mg = ma
T = m (g + a)
T = (80) (9.8 + 0.70)
T = 840 N
b)
d = distance traveled in upward direction = 13 m
= Work done by tension force
Work done by tension force is given as
= T d
= (840) (13)
= 10920 J
c)
d = distance traveled in upward direction = 13 m
= Work done by person's weight
Work done by person's weight is given as
= - mg d
= - (80 x 9.8) (13)
= - 10192 J
d)
= Net force on the person = ma = 80 x 0.70 = 56 N
v₀ = initial speed of the person = 0 m/s
v = final speed
Using work-energy theorem
d = (0.5) m (v² - v₀²)
(56) (13) = (0.5) (80) (v² - 0²)
v = 4.3 m/s
Answer:
Explanation:
The question says that, "The closest star to the earth is 2 light years away. Calculate this distance in SI units".
Given that,
The distance between the closest star and the Earth is 2 light years.
The SI unit of distance is m. It means we need to convert light years to meters. We know that,
2 light-years means,
So, the required distance is equal to .
Answer:
direction is given as
South of West
Explanation:
Part b)
displacement is given as
now we will have
total displacement is given as
direction is given as
South of West
To solve this problem we will start by defining the length of the shortest stick as 'x'. And the magnitude of the longest stick, according to the statement as
Both cover a magnitude of 8.32 ft, therefore
Now solving for x we have,
Therefore the shorter stick is 2.695ft long.