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).
Answer:
The maximum height reached by the ball is 16.35 m.
Explanation:
Given;
initial velocity of the ball, u = 17.9 m/s
the final velocity of the ball at the maximum height, v = 0
The maximum height reached by the ball is given by;
v² = u² + 2gh
During upward motion, gravity is negative
v² = u² + 2(-g)h
v² = u² - 2gh
0 = u² - 2gh
2gh = u²
h = u² / 2g
h = (17.9)² / (2 x 9.8)
h = 16.35 m
Ttherefore, the maximum height reached by the ball is 16.35 m.
No,
To emit light an electron has to jump down to a lower energy level but in an electron is unable to go any lower in ground state.
