Answer:
She can swing 1.0 m high.
Explanation:
Hi there!
The mechanical energy of Jane (ME) can be calculated by adding her gravitational potential (PE) plus her kinetic energy (KE).
The kinetic energy is calculated as follows:
KE = 1/2 · m · v²
And the potential energy:
PE = m · g · h
Where:
m = mass of Jane.
v = velocity.
g = acceleration due to gravity (9.8 m/s²).
h = height.
Then:
ME = KE + PE
Initially, Jane is running on the surface on which we assume that the gravitational potential energy of Jane is zero (the height is zero). Then:
ME = KE + PE (PE = 0)
ME = KE
ME = 1/2 · m · (4.5 m/s)²
ME = m · 10.125 m²/s²
When Jane reaches the maximum height, its velocity is zero (all the kinetic energy was converted into potential energy). Then, the mechanical energy will be:
ME = KE + PE (KE = 0)
ME = PE
ME = m · 9.8 m/s² · h
Then, equallizing both expressions of ME and solving for h:
m · 10.125 m²/s² = m · 9.8 m/s² · h
10.125 m²/s² / 9.8 m/s² = h
h = 1.0 m
She can swing 1.0 m high (if we neglect dissipative forces such as air resistance).
The magnitude of Alioth ( the brightest star in the big dipper ) is 1.76 and it is about 81 light years distant from Earth.
(a) We will use the equation v = u + at
Initial velocity u = 5.00 m/s
Acceleration a = 0.0600 m/s²
time = 8 min = 8 x 60 = 480 s
Final velocity
= u + at
= 5.00 + 0.0600(480)
= 33.8 m/s
The final velocity is 33.8 m/s
Answer:
Black bodies are good absorber of light waves from the sun, while shining surfaces are good reflector of the light waves.
Explanation:
Generally, a black surface or material tends to absorb light waves while under the sun, while a shiny surface is a good reflector of the waves. This is because the black material is a good absorber, and also a good emitter.
The shiny necklace can only absorb little light waves from the sun, thus it reflects most of the light waves. The reflection is the reason for the small circles of light seen around the yard.
However, when in a cool environment the black shirt would cools faster (good emitter) than the shiny necklace.