Register to reply

Physics gr11 review (acceleration)

by justme_girl04
Tags: acceleration, velocity
Share this thread:
Sep14-10, 08:25 PM
P: 2
1. The problem statements, all variables and given/known data

1. a 100m long train accelerates uniformly from rest. If the front of the train passes a railway worker 150m down the track at a speed of 25m/s, what will be the speed of the last car as it passes the worker?

2. a hot air baloon is rising up with a constant velocity of 4m/s. As the balloon reaches a height of 4m above the ground the balloonist accidentally drops a can of pop over the edge of the basket. How long does it take the pop can to reach the ground?

3.a stone is dropped from the roof of a high building. a second stone is droped 1s later. How far apart are the stones when the second one reached the speed of 23m/s?

3. a rock is dropped from a seacliff and the sound of it stirking the ocean is heard 3s later. If the speed of sound is 330m/s, how high is the cliff?

2. Relevant equations
These are the equations we were given to solve the questions:
(it might look messy, f is final and t is time)

honestly i tried doing these, but i just dont get it!
Phys.Org News Partner Science news on
What lit up the universe?
Sheepdogs use just two simple rules to round up large herds of sheep
Animals first flex their muscles
Sep14-10, 08:56 PM
P: 14
1. 150/25 = 250/x
x = 41.6666667m/s

2. this one is weird. can't help. are you sure you copied all the data?

3. vf^2=vi+2ad
d=27 m (stone 1)

d = (vi+vf/2)t
27 = (0+ 27/2)t
t=2 seconds( the first stone reached 27m in two seconds)

2s -1s = 1s so we want to calculate the position of stone 2 at one seconds so

d = vi + .5at^2
d = 0 + .5*9.8*1^2
d = 4.9m

21 - 4.9 = 22.1m difference

4. 3s * 330m / 1s = 990 m

have no clue if any of these are correct. please check my work guys
Sep15-10, 09:07 PM
P: 2
Hey thanks for the help, the first and third make sense.. yea it know the second is weird but i read the question over and thats what it says. the 4th one is way off lol, it was a pretty long solution that came to a heights of h=4.9(2.9)^2

Register to reply

Related Discussions
Exam review question (acceleration) Introductory Physics Homework 2
Gr11 Percentage of Kinetic Energy Introductory Physics Homework 3
Physics review site? General Physics 1
Gr11 Physics Forces Introductory Physics Homework 10
Physics review Introductory Physics Homework 6