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).
An angle of refraction of 90-degrees
Answer:
Nulo
Explanation:
Se o numero que aumenta for o mesmo que diminui, se torna nulo, pois nenhum passa a vencer o outro.
-- We already know the rate of revolutions per time ...
it's 1 revolution per 0.065 sec. We just have to
unit-convert that to 'per minute'.
(1 rev / 0.065 sec) x (60 sec / min) = (1 x 60) / (0.065) = <em>923 RPM</em> (rounded)
_______________________________
-- 1 revolution = 2π radians
(2π rad) / (0.065 sec) = (2π / 0.065) = <em>96.66 rad/sec</em> (rounded)
