Posted by Tony on .
i know this might seem kind of long. but if you could please help me, i'd greatly appreciate it.
a. suppose you have a tug of war with a friend who is the same size and weight as you are. You both pull as hard as you can, but neither of you seems to be winning. You move a little one way or the other, but mostly you are just at rest (although sweating some). Compare the magnitude of the force exerted by you on your friend, with the magnitude of the force exerted by your friend on you. Are they the same or different? If they are not the same, which is larger? Why or why not?
b. Now you have a tug of war with your kid sister (who is much smaller and lighter than you). Again you both pull hard but end in a standoff with neither of you moving much. Compare the magnitude of the force exerted by you on your sister, with the magnitude of the force she exerts on you. Are they the same or different? If they are not the same, which is larger? Why or why not?
c. The next tug of war is still with your kid sister but she is now standing on her skateboard. You can now make her roll across the floor (with constant speed) when you pull hard. In this situation compare the magnitude of the force exerted by you on your sister, with the magnitude of the force she exerts on you. Are they the same or different? If they are not the same, which is larger? Why or why not?
d. Now you pull your sister across the floor so that she moves with increasing speed (accelerates). Compare the magnitude of the force exerted by you on your sister, with the magnitude of the force she exerts on you. Are they the same or different? If they are not the same, which is larger? Why or why not?
e. Due to the drivers not paying attention, a small car and a big truck collide, both are initially moving at 5mph towards each other. Compare the magnitude of the force the truck exerts on the car to the magnitude of the force the car exerts on the truck. Which vehicle would you rather ride in? Describe why you made your choice.
i know a and b are equal.
but for ce. some ppl say they are all equal because newton's third law says so.
but some say they are not equal.
for example for e. the force is going towards the car because the truck has a greater force.
can someone please help me.

drwls please read 
Damon,
In all cases they are equal and opposite. In some of your cases, the force causes one or in e, both to accelerate. That does not mean the magnitude of the force is different on each. The force just has a different effect on each.
In part e, the car acceleration is much greater than the truck acceleration for the same force on both, so ride in the truck. 
drwls please read 
drwls,
You posted this twice. I answered already, attempting to get you to learn how Newton's Third Law applies, and I agree with Damon.

drwls please read 
Tony,
okay. but for D. there is acceleration. can you explain.

drwls please read 
bn,
seriously dude i need to finish this prelab

drwls please read 
bn,
remember, even if F is the same (which it always is in a collision), mass and acceleration may not be. smaller mass = greater acceleration because F = F and
ma = ma, so if one mass is smaller, its a must be larger to equalize with the other side. 
Physical science 
Cynthia,
A 4.2 kilo b
Bag of surgar is on a counter how much work is required to put the bag on a shelf a distance of 0.60 m above the counter. J