Physics Homework for answers/also explain how to do them

In summary, the conversation covers topics such as physics and its challenges, including studying velocity and displacement. The first question involves finding the average velocity for a trip with engine problems, while the second question requires plotting a graph and applying equations to determine when two cars will pass each other. The third question involves calculating time and velocity in km/h for a fired bullet.
  • #1
hstudent321
1
0
Physics really stumps me, I try to study a lot but its not getting in my head... Anyway here are the questions i need help on. I tried doing the problem out but it confuses me.. SO far I'm going over velocity, displacement, like V=d/t and D=vt t=d/v


1) You drive your Miata from home at an average velocity of 80 km/h for 3 hrs. Halfway to your destination, your Miata develops some engine problems, and for 5hrs you "nurse" the car the rest of the way. What is your average velocity for the entire trip?

2) Two cars are headed in the same direction; one traveling 60 km/h is 20km ahead of the other traveling 80km/h.
A)What would the graph look like showing the motion of the two cars?
B) When does the faster car overtake the slower one?

3) A bullet is fired with a speed of 720.0 m/s.
A) What time is required for the bullet to strike a target 324 m away?

B) What is the velocity in km/h
 
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  • #2
You got to know the distance from Miata to home to do that question. The word 'nurse' implies you are going slower and so need to calculate the speed after stopping.
 
  • #3
2)
a) plot a graph on a piece of paper with speed/velocity on the side and time on the bottom (i'd just put 1hr, 2hr, 3hr etc for each of the velocities [unless you got given something])
b) those 3 equations that you have are just different ways of writing the same thing.
anyhow you have two velocities v1=60km/hr v2=80km/hr, when the cars pass each other t will be the same for both cars. so put both with respect to t (t=d/v). write out 2 equations so because the t's are the same d1/v1=d2/v2. you should be able to work this out from here.

3)
a) v=720m/s, d=324m -> you have an equation (t=d/v just sub the values in)
b) v=720m/s
1km=1000m -> 1km/1000m = 1
1hr=3600s -> 3600s/1hr =1
(you don't want to change the value so you need to multiply by 1)
720m/s x 1km/1000m x 3600s/1hr (so 720m/s x 1 x 1)
so this will cancel m and s and you'll be left with km/hr
 

1. How do I calculate velocity?

To calculate velocity, you need to divide the distance traveled by an object by the time it took to travel that distance. The formula for velocity is: velocity = distance/time. Make sure to use the appropriate units for distance and time (e.g. meters per second or kilometers per hour).

2. What is Newton's first law of motion?

Newton's first law of motion, also known as the law of inertia, states that an object will remain at rest or in motion at a constant velocity unless acted upon by an external force. In other words, an object will continue to do what it's already doing unless something causes it to change.

3. How do I calculate work?

To calculate work, you need to multiply the force applied to an object by the distance the object moves in the direction of that force. The formula for work is: work = force x distance. Again, make sure to use the correct units for force and distance (e.g. Newtons and meters).

4. What is the difference between speed and velocity?

Speed is a measure of how fast an object is moving, while velocity is a measure of both the speed and direction of an object's motion. In other words, velocity takes into account the direction of an object's motion, while speed does not.

5. What is the difference between potential and kinetic energy?

Potential energy is the energy an object has due to its position or condition, while kinetic energy is the energy an object has due to its motion. Potential energy can be converted into kinetic energy, and vice versa, but they are two distinct forms of energy.

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