Answer:
For elliptical orbits: seldom
For circular orbits: always
Explanation:
We start by analzying a circular orbit.
For an object moving in circular orbit, the direction of the acceleration (centripetal acceleration) is always perpendicular to the direction of motion of the object.
Since acceleration has the same direction of the force (according to Newton's second law of motion), this means that the direction of the force (the centripetal force) is always perpendicular to the velocity of the object.
So for a circular orbit,
the direction of the velocity of the satellite is always perpendicular to the net force acting upon the satellite.
Now we analyze an elliptical orbit.
An elliptical orbit correponds to a circular orbit "stretched". This means that there are only 4 points along the orbit in which the acceleration (and therefore, the net force) is perpendicular to the direction of motion (and so, to the velocity) of the satellite. These points are the 4 points corresponding to the intersections between the axes of the ellipse and the orbit itself.
Therefore, for an elliptical orbit,
the direction of the velocity of the satellite is seldom perpendicular to the net force acting upon the satellite.
Answer:
Option C is the correct answer
Explanation:
Distance travelled by car during reaction time
The car stopped before hitting the animal by
Distance travelled during deceleration is
Hence by
We have
Option C is the correct answer
120 volts for most home a phone charger can convert 120 volts ac to 5 volts dc
Answer:
-19.259m/s
Explanation:
Given;
Final velocity = 19m/s
time t = 1.6s
u is the initial velocity
g is the acceleration due to gravity = 9.81m/s²
Using the equation of motion to first get the initial velocity of the shell:
v = u-gt
19 = u - (9.81)(1.6)
19 = u - 15.696
u = 19+15.696
u = 34.696m/s
The initial velocity of the shell is 34.696m/s
Next is to find the speed of the shell 5.5s after the launch
Using the equation of motion:
v = u-gt
v = 34.696-9.81(5.5)
v = 34.696 - 53.955
v = -19.259m/s
<em>The negative value of the velocity shows that the velocity is travelling in the downward direction</em>
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