Answer:
a) u = 30.29 m/s
b) t = 2.09 s
Explanation:
given,
velocity = 45 m/s
angle (θ) = 50°
horizontal velocity = 45 cos 50°
time taken to reach 150 m.
times =
t = 5.19 s
a) height of arrow
s = 46.78 m
v² - u² = 2 g s
u² = 2 × 9.81 × 46.78
u = 30.29 m/s
b) time taken by the apple =
= 3.09 s
time after which it has to be thrown = 5.19-3.09 = 2.1 s
Answer:
(a) r = 1.062·R =
(b) r =
(c) Zero
Explanation:
Here we have escape velocity v given by
and the maximum height given by
Therefore, when the initial speed is 0.241v we have
v = so that;
v² =
v² =
is then
Which gives
or
r = 1.062·R
(b) Here we have
Therefore we put in the maximum height equation to get
From which we get
r = 1.32·R
(c) The we have the least initial mechanical energy, ME given by
ME = KE - PE
Where the KE = PE required to leave the earth we have
ME = KE - KE = 0
The least initial mechanical energy to leave the earth is zero.