It is because of momentum. Velocity can change if an object changes direction since velocity depends on both the speed and direction
The answer is d.8,120 foot-pounds
Let x = the angle of elevation for shooting the arrow.
Assume
g = 9.8 m/s²
No wind resistance
The vertical launch velocity is 25.1 sin(x) m/s
The horizontal velocity is 25.1 cos(x) m/s
The time of flight is
24/[25.1 cos(x)] s = 0.9562 sec(x) s
Therefore
0.5*[0.9562 sec(x)]*(9.8) = 25.1 sin(x)
4.6854 = 25.1* sin(x)cos(x)
sin(2x) = 0.3733
2x = sin⁻¹ 0.3733 = 21.92 deg
x = 10.96 deg
Answer: 11 degrees (nearest integer)
The answer would be letter choice B
Answer:
a) t=24s
b) number of oscillations= 11
Explanation:
In case of a damped simple harmonic oscillator the equation of motion is
m(d²x/dt²)+b(dx/dt)+kx=0
Therefore on solving the above differential equation we get,
x(t)=A₀
where A(t)=A₀
A₀ is the amplitude at t=0 and
is the angular frequency of damped SHM, which is given by,

Now coming to the problem,
Given: m=1.2 kg
k=9.8 N/m
b=210 g/s= 0.21 kg/s
A₀=13 cm
a) A(t)=A₀/8
⇒A₀
=A₀/8
⇒
applying logarithm on both sides
⇒
⇒
substituting the values

b) 

, where
is time period of damped SHM
⇒
let
be number of oscillations made
then, 
⇒