Answer:
8.16 J
Explanation:
Applying,
W = ke²/2................. Equation 1
Where W = work done in stretching the spring, k = spring constant, e = extension
make k the subject of the equation
k = 2W/e²................ Equation 2
From the question,
Given: W = 4 J, e = 14 cm = 0.14 m
Substitute these values into equation 2
k = 2(4)/0.14²
k = 8/0.0196
k = 408.16 N/m
If stretchd 20 cm from its natural length,
Therefore,
e = 20 cm = 0.2 m
W = 408.16(0.2²)/2
W = 8.16 J
To solve the astronaut's problem it is necessary to quickly consider the conservation of the moment.
By definition we know that,
Initial Momentum = Final Momentum
Where,
Human mass
Tank mass
v is the initial and final velocity of each object
In the case of the initial part we know that it is in a state without movement with respect to the ship.
In the case of the final moment there is a speed injection thanks to the oxygen tank, then,
Re-arrange to find the final velocity for astronaut,
Replacing
The astronaut has 4 minutes of air and must travel 200 meters therefore,
Re-arrange to find the time,
<em>He/She will reach the spacecraft within the stipulated time</em>
Answer:
(1) Exercise should be painful in order for it to be beneficial. FALSE
(2) Proper progression involves a gradual increase in the level of exercise. TRUE
(3) Exercising on a regular, consistent basis provides you with the best results. TRUE
Explanation:
(1) It is a false statement because whenever we do exercise, it should not be painful, it should be comfortable to some extent for a person, if it will be painful then it means one cant get the true and genuine benefit from the exercise.
(2) It is very much true because one must keep on increasing the level of his/her exercise gradually with the passage of time, it will make his/her body synchronized with the exercise properly.
(3) It is also a true statement because, one must use variety of exercises in his/her workout session targeting different muscles and different areas and parts of the body to make exercise really beneficial.