. A person travels by car from one city to another with different constant speeds between pairs of cities. She drives for 30.0 m
2 answers:
Answer:
a) The average speed for the trip is 52.9
b) The distance between the initial and final cities along the route is 90 km.
Explanation:
First, knowing that 1 hour is 60 minutes, the conversion of the times in which you travel at each speed or for lunch or buy gas is performed:
- 30 minutes: 0.5 hr
- 12 minutes: 0.2 hr
- 45 minutes: 0.75 hr
- 15 minutes: 0.25 hr
Velocity is a physical quantity that expresses the relationship between the space traveled by an object in the following way:
Then:
change of position=velocity*time
So, in this case:
- change of position 1= 0.5 hr* 80
= 40 km
- change of position 1= 0.2 hr* 100
- change of position 1= 0.75 hr* 40
So, the total distance traveled is change of position 1+ change of position 2 + change of position 3= 40 km + 20 km + 30 km= 90 km
And the total elapsed time is considering the lunch time and gas purchase added to the time to make the journey to the technical stop: 0.5 hr + 0.2 hr + 0.75 hr + 0.25 hr= 1.7 hr
So, the velocity is:
Finally:
<u><em>a) The average speed for the trip is 52.9 </em></u><u><em></em></u>
<u><em>b) The distance between the initial and final cities along the route is 90 km.</em></u>
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Answer:
a) The distance of the object from the center of the Earth is 8.92x10⁶ m.
b) The initial acceleration of the object is 5 m/s².
Explanation:
a) The distance can be found using the equation of gravitational force:
Where:
G: is the gravitational constant = 6.67x10⁻¹¹ Nm²/kg²
M: is the Earth's mass = 5.97x10²⁴ kg
m: is the object's mass = 0.4 kg
F: is the force or the weight = 2.0 N
r: is the distance =?
The distance is:
Hence, the distance of the object from the center of the Earth is 8.92x10⁶ m.
b) The initial acceleration of the object can be calculated knowing the weight:
Where:
W: is the weight = 2 N
a: is the initial acceleration =?
Therefore, the initial acceleration of the object is 5 m/s².
I hope it helps you!
Answers:
a)
b)
c)
d)
Explanation:
For this situation we will use the following equations:
(1)
(2)
Where:
is the <u>height of the model rocket at a given time</u>
is the i<u>nitial height </u>of the model rocket
is the<u> initial velocity</u> of the model rocket since it started from rest
is the <u>velocity of the rocket at a given height and time</u>
is the <u>time</u> it takes to the model rocket to reach a certain height
is the <u>constant acceleration</u> due gravity and the rocket's thrust
<h2>a) Time it takes for the rocket to reach the height=4.2 m</h2>
The average velocity of a body moving at a constant acceleration is:
(3)
For this rocket is:
(4)
Time is determined by:
(5)
(6)
Hence:
(7)
<h2>b) Magnitude of the rocket's acceleration</h2>
Using equation (1), with initial height and velocity equal to zero:
(8)
We will use :
(9)
Finding :
(10)
<h2>c) Height of the rocket 0.20 s after launch</h2>
Using again but for
:
(11)
(12)
We will use equation (2) remembering the rocket startted from rest:
(13)
(14)
Finally:
(15)