Answer:
K remains constant
Explanation:
The magnetic force does not do any work on the ion.
In fact, the magnetic force due to a magnetic field is always perpendicular to the motion of the charge itself. Keep in mind that the work done by a force is given by
where F is the magnitude of the force, d is the displacement of the particle, and is the angle between the direction of the force and the displacement. Since the magnetic force is perpendicular to the displacement of the ion, then and , so the work done is zero.
For the work-energy theorem, the work done on the ion is equal to the variation of its kinetic energy:
However, since W=0, then , which means that the kinetic energy of the ion does not change.
Answer: a) 10.4km
b) 0.62h
C) 17km/h
d) 9.1km/h
Explanation:
A) suppose you move in the positive direction of an x axis, from a first position of x1 = 0 to a second position of x2 at the station. That second position must be at x2 = 8.4 km + 2.0 km = 10.4 km.
B) time interval Dtwlk (= 0.50 h), but we don't know the driving time interval Dt/dr. However, we know that for the drive the displacement Dx/dr is 8.4 km and the average velocity vavg,dr is 70 km/h.
This average velocity is the ratio of the displacement for the drive to the time interval for the drive:
dv = dx/ dt
dt = dx/dv = 8.4/70 = 0.12h
t = ti + two
t = 0.12 + 0.50 = 0.62h
C) avg speed for the entire trip is the ratio of the displacement of 10.4 km for the entire trip to the time interval of 0.62 h for the entire trip.
Avg v = distance/time
10.4/0.62 = 16.8km/h
D) average speed is the ratio of the total distance you move to the total time interval you take to make that move. The total distance is 8.4 km + 2.0 km + 2.0 km = 12.4 km. The total time interval is 0.12 h + 0.50 h + 0.75 h = 1.37 h.
Avg speed = 12.4/1.37 = 9.1km/h
Answer:
18N
Explanation:
Mechanical Advantage of crowbar (lever), MA = Length of effort arm / Length of resistance arm
Therefore, MA = 28 cm / 4.2 cm = 6.667
Force required to pull the nail, F = Friction force / MA
ie, F = 120 N / 6.667 = 18 N
Answer:
Inertia is the reason that people in cars need to wear seat belts. Instead, the riders continue moving forward with most of their original speed because of their inertia. If the driver is wearing a seat belt, the seat belt rather than the windshield applies the unbalanced force that stops the driver's forward motion.