Answer: h = 0.30 m
Explanation:
A person jumping from height h would possess potential energy = m g h
which will convert completely into kinetic energy as person hits the ground. Now, the maximum energy absorbed by the person can be = 200 J
m = 67 kg
g = 9.8 m/s²
⇒ m g h = 200 J
⇒ h = 200 J / (67 kg × 9.8 m/s²) = 0.30 m
Hence, a person can land safely on both legs without breaking them from a height of 0.30 m only.
6.
A. 1575 - 1265 = 310J
B. KE 1/2 MV^2
V=√2·KE/M = √2(310)/12 V = 7.2mls
C. PE = 1265 = mgh
h= 1265/mg = 1265/(12)(92) h= 10.8m
7.
A. KE = 1/2 mv^2 0.5(5)(12)^2 KE = 360J
B. PE = mgh = (5)(9.8)(2.6) PE = 127.4J
C. ME = KE + PE = 360 + 127.4 ME = 487.4J
Answer:
625 piece.
Explanation:
Let n be the required no of piece
200 litre = 200 x 10⁻³ m³ = 200 x 10⁻³ x 10³ kg = 200 Kg
mass of ice piece = n x 30 x /1000
Heat lost by ice pieces = (n x 30) / 1000 x ( 80 + 1 x 16⁰C)
Heat gained by water = 200 x 1 x 9⁰C
Heat lost = Heat gained
(n x 30) /1000 x ( 80 + 16 ) =200 x 9
2.88 n = 1800
n = 625
Answer:
As a science fair project, you want to launch an 950g model rocket straight up and hit a horizontally moving target as it passes 33.0m above the launch point. The rocket engine provides a constant thrust of 20.0N . The target is approaching at a speed of 18.0m/s . At what horizontal distance between the target and the rocket should you launch?
= 43.56m
Explanation:
acceleration =
(20 - (0.95 * 9.8) )/ (0.95)
= 10.68 / 0.95
= 11.24 m/s²
we use
s = ut + (1/2) at²
Given that
s= 40
u =0
s = 0 * t + (1/2) (11.24)t²
t = √(66/1.24)
t = √5.87
t = 2.42sec
hence
Horizontal distance = 18 * 2.42
= 43.56m
Explanation:
gravitational potential energy at the top of the hill, which transforms into kinetic energy as he moves bottom of the hill
that's mean potential energy transfoms into kinetic energy
