Answer: 89.803 ft
Explanation:
The complete question is written below:
An astronaut on the moon throws a baseball upward. The astronaut is 6ft, 6 in. tall and the initial velocity of the ball is 30 ft per second. The height s of the ball in feet is given by the equation,s=-2.7t^2+30t+6.5, where t is the number of seconds after the ball is thrown.
The ball will never reach a height of 100ft. How can this be determined algebraically?
We have the following equation that expresses the height
as a function of time:
(1)
Now, if we wan to find the maximum height the baseball reaches and prove it is less than 100 ft, we firstly have to find the time
the whole parabolic movement lasts and then find
which is the time it takes the baseball to reach its maximum height.
So, if we want to calculate
, this is fulfilled when
, when the baseball hits the ground:
(2)
This is a quadratic equation of the form
, and we have to use the quadratic formula if we want to find
:
(3)
Where
,
,
Substituting the known values and choosing the positive result of the equation:
(4)
Then we can calculate
:
(5)

(6)
Substituting (6) in (1):
(7)
(8) This is the maximum height the baseball reaches, as we can see it is less than 100 ft
Answer:
241.7 s
Explanation:
We are given that
Charge of particle=
Kinetic energy of particle=
Initial time=
Final potential difference=
We have to find the time t after that the particle is released and traveled through a potential difference 0.351 V.
We know that

Using the formula


Initial voltage=

Using the formula





Hence, after 241.7 s the particle is released has it traveled through a potential difference of 0.351 V.
Answer:
Weight needed to balance the bar is 
Explanation:
Given the weight of the bar is 
The length of the bar is 
The weight of the bar will be uniformly distributed over the entire span. We will consider this as a point load acting in the middle of span length, which is at a distance of
from both ends.
Now applying momentum equation about balanced load we get, (see attachment)

The figure shown above is series combination as the two resistors (bulb) are there which are then connected to the battery
so i conclude from the above options given the option is B
hope it helps