Sally's average speed is <u>35.3 mi/h.</u>
Average speed of a body is the total distance traveled in the given time interval.
Express the distance d traveled in miles.
![d=\frac{97 km}{1.6 km/m\\i} \\ = 60 mi](https://tex.z-dn.net/?f=%20d%3D%5Cfrac%7B97%20km%7D%7B1.6%20km%2Fm%5C%5Ci%7D%20%5C%5C%20%3D%2060%20mi%20)
Express the time t traveled in hours.
![t =\frac{102 min}{60 min/hr}\\ = 1.7 h](https://tex.z-dn.net/?f=%20t%20%20%3D%5Cfrac%7B102%20min%7D%7B60%20min%2Fhr%7D%5C%5C%20%3D%201.7%20h%20)
Calculate the average speed v.
![v =\frac{d}{t} \\ =\frac{60 mi}{1.7h} \\ = 35.3 mi/h](https://tex.z-dn.net/?f=%20v%20%3D%5Cfrac%7Bd%7D%7Bt%7D%20%5C%5C%20%3D%5Cfrac%7B60%20mi%7D%7B1.7h%7D%20%5C%5C%20%20%20%3D%2035.3%20mi%2Fh%20%20%20)
Her average speed is 35.3 mi/h, which is less than the speed limit of 65 mi/h.
However, the average speed of an object is different from its instantaneous speed. It could be possible that at the time when the officer apprehended her, Sally could have been travelling at a speed greater than the prescribed speed limit, which would have prompted the officer to issue a speeding ticket to her.
Thus, the average speed of a person cannot be considered as a bench mark for speeding offences, since her instantaneous speed could have been higher than the speeding limit and yet she could have had an average speed less than the speeding limit.
Answer:
She does a work of 689.44 J in the snow.
Explanation:
A force is said to do work when it alters the state of motion of a body. The work of the force on that body will be equivalent to the energy needed to move it.
In other words, Work is a form of energy transmission between bodies. In order to carry out work, a force must be exerted on a body and it must move.
The work is equal to the product of the force times the distance and the cosine of the angle that exists between the direction of the force and the direction that the moving point or object travels:
W= F*d* cos Ф
Work W is measured in joules (J), force is measured in newtons (N), and displacement in meters (m).
In this case:
- F= 180 N
- d=5 m
- Ф= 40 degrees
Replacing:
W= 180 N*5 m* cos 40
Solving:
W= 689.44 J
<u><em>She does a work of 689.44 J in the snow.</em></u>
Answer:
4hrs
Explanation:
speed =72km/hr
distance= 300km
time =?
<h3>
<u>speed = distance/time</u></h3>
using this formula we make time the subject of the formula
time = distance/speed
time = 300/72
time = 4.1
therefore,
<em>time is equal to 4hrs</em>
Answer:
a) True
b)False
c)False
• Had to complete the question first.
A block slides at constant speed down a ramp while acted on by three forces: its weight, the normal force, and kinetic friction. Respond to each statement, true or false.
(a) The combined net work done by all three forces on the block equals zero.
(b) Each force does zero work on the block as it slides.
(c) Each force does negative work on the block as it slides.
Explanation:
Net work is the change in kinetic energy, which leads to final kinetic energy - our initial kinetic energy this is the formula for net work. This is the working energy theorem, a theorem that states that the net work on an object induces a change in the object's kinetic energy.