B. Static friction force - static friction is the force put on an object to keep that same object at rest
Answer:
Average speed: 0.5 m/s. Average velocity: 0
Explanation:
Average speed is given by:
where
d is the total distance covered (the length, of one lap of the track, so d = 400 m)
t is the time taken to cover that distance (so, t = 800 s)
Substituting,
Instead, average velocity is defined as
where this time,
d is the displacement, which is the vector connecting the starting point to the final point of the motion
t is still the time taken (800 s)
However, in this case the walker starts and finishes his trip at the same point: therefore, the displacement is zero (d=0), and this means that the average velocity is zero as well.
Answer:
if one bulb burns out the other will also turn off because they are connected to each other.
The mass is rising with a constant speed.
=> So it has no vertical acceleration.
=> So there is no net vertical force acting on it.
=> So the sum of the vertical forces on it is zero.
There are two vertical forces acting on the mass.
=> the force of gravity, pulling it down
=> the tension in the cable, pulling it up.
The force of gravity acting on the mass (its weight) is (mass) x (gravity).
=> That's (120 kg) x (9.8 m/s²) downward.
=> That's 1,176 newtons downward.
If the vertical forces add up to zero, the other force ... the tension in the cable ... must be the same magnitude in the opposite direction.
=> The force of tension in the cable is <em>1,176 newtons upward</em>.
Answer:
\d{4}$
Explanation:
In regular expression, the '\d' is used to match digits (from 0 to 9). The '{4}' simply to denote the number of digits needed to match (in this case, 4 in length). Finally, in order to match at the end of the line, the '$' is added.
Therefore the regular expression string for this is
\d{4}$