Answer:
v = 42.92 m/s
Explanation:
Given,
initial speed of the ball, v = 11 m/s
time taken to hit the ground = 5.5 m/s
velocity of the ball just before it hit the ground, v = ?
time taken by the ball to reach the maximum height
using equation of motion
v = u + at
final velocity = 0 m/s
0 = 11 - 9.8 t
t = 1.12 s.
time taken by the ball to reach the water from the maximum height
t' - 5.5 -1.12 = 4.38 s
using equation of motion for the calculation of speed just before it hit the water.
v = u + a t
v = 0 + 9.8 x 4.38
v = 42.92 m/s
Velocity of the ball just before it reaches the water is equal to v = 42.92 m/s
Answer:
Condition
![\frac{m}{R} \geq \frac{c^{2} }{2*g}](https://tex.z-dn.net/?f=%5Cfrac%7Bm%7D%7BR%7D%20%5Cgeq%20%5Cfrac%7Bc%5E%7B2%7D%20%7D%7B2%2Ag%7D)
Explanation:
Basically black hole is an object from which light rays can not escape it means to go out from gravitational field , that body should thrown with speed greater then light.
Let's do some calculation
Gravitational potential at surface =![-\frac{G*M*m}{R}](https://tex.z-dn.net/?f=-%5Cfrac%7BG%2AM%2Am%7D%7BR%7D)
If we give kinetic energy equal to magnitude of Potential energy as on surface it will escape.
=![-\frac{G*M*m}{R}](https://tex.z-dn.net/?f=-%5Cfrac%7BG%2AM%2Am%7D%7BR%7D)
⇒![\frac{m}{R} =\frac{c^{2} }{2*G}](https://tex.z-dn.net/?f=%5Cfrac%7Bm%7D%7BR%7D%20%3D%5Cfrac%7Bc%5E%7B2%7D%20%7D%7B2%2AG%7D)
It will be more better for black hole if above ratio (analogous to density ) is more then above calculated
Answer:
B. 0.98 m/s
Explanation:
This is because we use the simple formula of dividing the distance by the time. In which case would be 13.69m (distance) divided by 13.92s (time) and we will get 0.983477011 or 0.98m/s (your answer)
I hope this made sense and hoped it helped. Good luck with your test luv :)
Answer:
Ec = 6220.56 kcal
Explanation:
In order to calculate the amount of Calories needed by the climber, you first have to calculate the work done by the climber against the gravitational force.
You use the following formula:
(1)
Wc: work done by the climber
g: gravitational constant = 9.8 m/s^2
M: mass of the climber = 78.4 kg
h: height reached by the climber = 5.42km = 5420 m
You replace in the equation (1):
(2)
Next, you use the fact that only 16.0% of the chemical energy is convert to mechanical energy. The energy calculated in the equation (2) is equivalent to the mechanical energy of the climber. Then, you have the following relation for the Calories needed:
![0.16(E_c)=4,164,294.4J](https://tex.z-dn.net/?f=0.16%28E_c%29%3D4%2C164%2C294.4J)
Ec: Calories
You solve for Ec and convert the result to Cal:
![E_c=\frac{4,164,294.4}{016}=26,026,840J*\frac{1kcal}{4184J}\\\\E_c=6220.56\ kcal](https://tex.z-dn.net/?f=E_c%3D%5Cfrac%7B4%2C164%2C294.4%7D%7B016%7D%3D26%2C026%2C840J%2A%5Cfrac%7B1kcal%7D%7B4184J%7D%5C%5C%5C%5CE_c%3D6220.56%5C%20kcal)
The amount of Calories needed by the climber was 6220.56 kcal
Answer:
The answer is below
Explanation:
The maximum height (h) of a projectile with an initial velocity of u, acceleration due to gravity g and at an angle θ with the horizontal is given as:
![h=\frac{u^2sin^2\theta}{2g}](https://tex.z-dn.net/?f=h%3D%5Cfrac%7Bu%5E2sin%5E2%5Ctheta%7D%7B2g%7D)
Given that the two projectile has the same height.
![For\ the\ first\ projectile\ with\ an\ angle\ \60^0 \ with\ the\ horizontal\ and initial\ velocity\ u_1:\\\\h=\frac{u_1^2sin^260}{2g} =\frac{0.75u_1^2}{2g} \\\\For\ the\ second\ projectile\ with\ an\ angle\ \30 \ with\ the\ horizontal\ and initial\ velocity\ u_2:\\\\h=\frac{u_2^2sin^230}{2g} =\frac{0.25u_2^2}{2g}\\\\\frac{0.25u_2^2}{2g}=\frac{0.75u_1^2}{2g}\\\\0.25u_2^2=0.75u_1^2\\\\\frac{u_1^2}{u_2^2} =\frac{0.25}{0.75} \\\\\frac{u_1^2}{u_2^2}=\frac{1}{3} \\](https://tex.z-dn.net/?f=For%5C%20the%5C%20first%5C%20projectile%5C%20with%5C%20an%5C%20angle%5C%20%5C60%5E0%20%5C%20with%5C%20the%5C%20horizontal%5C%20and%20initial%5C%20velocity%5C%20u_1%3A%5C%5C%5C%5Ch%3D%5Cfrac%7Bu_1%5E2sin%5E260%7D%7B2g%7D%20%3D%5Cfrac%7B0.75u_1%5E2%7D%7B2g%7D%20%5C%5C%5C%5CFor%5C%20the%5C%20second%5C%20projectile%5C%20with%5C%20an%5C%20angle%5C%20%5C30%20%5C%20with%5C%20the%5C%20horizontal%5C%20and%20initial%5C%20velocity%5C%20u_2%3A%5C%5C%5C%5Ch%3D%5Cfrac%7Bu_2%5E2sin%5E230%7D%7B2g%7D%20%3D%5Cfrac%7B0.25u_2%5E2%7D%7B2g%7D%5C%5C%5C%5C%5Cfrac%7B0.25u_2%5E2%7D%7B2g%7D%3D%5Cfrac%7B0.75u_1%5E2%7D%7B2g%7D%5C%5C%5C%5C0.25u_2%5E2%3D0.75u_1%5E2%5C%5C%5C%5C%5Cfrac%7Bu_1%5E2%7D%7Bu_2%5E2%7D%20%3D%5Cfrac%7B0.25%7D%7B0.75%7D%20%5C%5C%5C%5C%5Cfrac%7Bu_1%5E2%7D%7Bu_2%5E2%7D%3D%5Cfrac%7B1%7D%7B3%7D%20%5C%5C)
![\\\frac{u_1}{u_2}=\sqrt\frac{1}{3}](https://tex.z-dn.net/?f=%5C%5C%5Cfrac%7Bu_1%7D%7Bu_2%7D%3D%5Csqrt%5Cfrac%7B1%7D%7B3%7D)