Answer:
The correct answer is 32.9 m/s
Explanation:
To solve this, we list out the known and the unknown variables as follows
Maximum allowable acceleration = 1.34 m/s²
Distance between sttions = 806 m
Therefore from the equation of motion
v = ut + 0.5·×at²
Where v = final velocity
u = initial velocity
S = distance covered
t = time
a = acceleration
Also v² = u² + 2·a·S
where u is the initial velocity, which we can take as u = 0, then
v² = 2·1.34·S = 2.68S m²/s² then
Also the train has to decelerate from maximum speed to stop at the next tran station wherev = 0, thus v² = u² -2·1.34·Z, so u² = 2.68Z
since u² = 2.68S from the previous calculation, then for v = 0
2.68S = 2.68Z thus S = Z which and to reach the next subway station S + Z must be = 806 m, then S = 806 m ÷ 2 = 403 m
and v² = 2.68S m²/s² = 1080.04 m²/s²
v = 32.9 m/s
The maximum speed a subway train can attain between stations is 32.9 m/s
A developing story hope it helped
Answer:
D. Both occur between objects independently whether they are in contact or not.
Explanation:
- The gravitational force is a force that is exerted between two (or more) objects having mass. This force is always attractive and its magnitude is given by
where G is the gravitational constant, m1 and m2 are the two masses, and r is the distance between the two masses.
- The electrical force is a force that is exerted between two (or more) objects having electrical charge. It can be either attractive or repulsive, depending on the sign of the two charges, and its magnitude is given by
where k is the Coulomb's constant, q1 and q2 are the two charges, and r the distance between the two charges.
Looking at both formulas, we see that the two forces are present even when the two objects are not in contact with each other (in fact, r can assume any value in the formula). They are said to be non-contact forces. Therefore, the correct option is
D. Both occur between objects independently whether they are in contact or not.
Average speed = (distance covered) / (time to cover the distance)
Tissa covered 60 meters in 10 seconds. Her average speed was
(60 m) / (10 sec) = 6 m/s.
That's the slope of the dotted line.
Lilly covered 60 meters in 8 seconds. Her average speed was
(60 m) / (8 sec) = 7.5 m/s .
That's the slope of the solid line.
Lilly covered the same distance in less time, and both girls
arrived at the finish line together. Technically, in science talk,
we would say that Lilly ran "faster", and her average speed
was "greater".
We can detect that by looking at the graph, because Lilly's line
has the characteristic of being "steeper", and we know that the
slope of the line on a distance/time graph is "speed".
