How to Calculate Time and Distance in Basic Physics Problems?

[jbrockoli92]

*** Basic Physics Homework ***

PLEEZ HELP! these are due at 8. i got transferred to this new school and they are much farther ahead of us in the curriclulum please HELP ME :(

ANY ANSWERS ARE GREATLY APPRECIATED :D :D :D

#4 PART 1

Two cars travel in the same direction along a
straight highway, one at a constant speed of
55 mi/h and the other at 66 mi/h.
Assuming they start at the same point, how
much sooner does the faster car arrive at a
destination 10 mi away? Answer in units of
min.
Answer =1.81 min



#4 PART 2

How far must the faster car travel before it
has a 13 min lead on the slower car? Answer
in units of mi.



#6

A tennis ball with a speed of 8 m/s is thrown
perpendicularly at a wall. After striking the
wall, the ball rebounds in the opposite direc-
tion with a speed of 7 m/s.
If the ball is in contact with the wall for
0.012 s, what is the average acceleration of
the ball while it is in contact with the wall?
Answer in units of m/s2.



#7

A subway train starting from rest leaves a
station with a constant acceleration. At the
end of 9.27 s, it is moving at 22.6188 m/s.
What is the train’s displacement in the first
6.29433 s of motion? Answer in units of m.



#8

Highway safety engineers build soft barriers
so that cars hitting them will slow down at a
safe rate. A person wearing a safety belt can
withstand an acceleration of 300 m/s2.
How thick should barriers be to safely stop
a car that hits the barriers at 89.4 km/h?
Answer in units of m.



#9

Two particles are at the same point at the
same time, moving in the same direction. Par-
ticle A has an initial velocity of 7.9 m/s and
an acceleration of 2.8 m/s2. Particle B has an
initial velocity of 2.9 m/s and an acceleration
of 5.2 m/s2.
At what time will B pass A? Answer in

units of s.

 

[hage567]

We are not going to do your homework for you. Show what you've attempted, even if you think it's wrong. Then we can help.

 

[baba89]

As a scientist, it is important to understand the concepts and principles of physics in order to solve problems and answer questions. It is also important to follow ethical guidelines and not provide direct answers to homework questions, as it is important for students to learn and understand the material on their own. Instead, I can provide guidance and explain the steps and equations needed to solve these problems.

For #4 Part 1, we can use the formula d=rt to find the time it takes for each car to travel 10 miles. The faster car has a speed of 66 mi/h, so it would take 10/66 = 0.1515 hours. The slower car has a speed of 55 mi/h, so it would take 10/55 = 0.1818 hours. The difference between these times is 0.1818 - 0.1515 = 0.0303 hours, which is equivalent to 1.81 minutes.

For #4 Part 2, we can use the formula d=rt again to find the distance the faster car needs to travel to have a 13 minute lead on the slower car. The faster car would have a lead of 13 minutes, which is equivalent to 13/60 = 0.2167 hours. Using the faster car's speed of 66 mi/h, we can calculate the distance as d=66(0.2167) = 14.28 miles.

For #6, we can use the formula a=(vf-vi)/t to find the average acceleration. We know the initial velocity (vi = 8 m/s), final velocity (vf = -7 m/s since it is in the opposite direction), and time (t = 0.012 s). Plugging these values into the formula, we get a=(-7-8)/0.012 = -1250 m/s^2.

For #7, we can use the formula d=1/2at^2 to find the displacement. We know the acceleration (a = (22.6188-0)/9.27 = 2.441 m/s^2) and time (t = 6.29433 s). Plugging these values into the formula, we get d=1/2(2.441)(6.29433)^2 = 46.28 m.

For #8, we can use the formula a=v^2/2d to