Math Is Fun Forum
You are not logged in.
- Topics: Active | Unanswered
Pages: 1
#1 2007-02-21 22:27:10
- Toast
- Real Member
- Registered: 2006-10-08
- Posts: 1,321
Elementary Physics
Assume friction = 0
A trolley of mass 2 kg travelling at 0.5ms-¹ collides with a stationary 1 kg trolley. The 2 kg trolley continues to move with a velocity of 0.1ms-¹ after the collision. What is the velocity of the 1 kg trolley?
What is the gravitational acceleration of a body of mass 10 kg on a planet where the gravitational field strength is 7N kg-¹?
I think for the second one I should do:
?And I'm clueless for the first.
Offline
#2 2007-02-21 22:32:45
- George,Y
- Member
- Registered: 2006-03-12
- Posts: 1,379
Re: Elementary Physics
(∑mv)-before = (∑mv)-after
Momentum constant
2kg*0.5ms-¹=2 kg*0.1ms-¹+1kg*?
So ?=0.8ms-¹
X'(y-Xβ)=0
Offline
#3 2007-02-22 01:32:32
- Jai Ganesh
- Administrator
- Registered: 2005-06-28
- Posts: 48,402
Re: Elementary Physics
I agree with George,
I remember the formula I had read long back
where m1 and m2 are the masses of the first and the second bodies, u1 and u2 their intial velocities and v1 and v2 their final velocities.
Thus, for this problem,
Total momentum before collision= 1 kgm/s.
Total momentum after the collision= 0.2 + 1v
where v is the velcoity of the 1 kg trolley.
Therefore, v= 0.8 m/s.
It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.
Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.
Offline
#4 2007-02-22 01:38:39
- Toast
- Real Member
- Registered: 2006-10-08
- Posts: 1,321
Re: Elementary Physics
Ok I think that makes sense, thanks.
Also, is P usually used to represent momentum? I ask because m is already reserved for mass.
Offline
#5 2007-02-22 01:43:07
- Jai Ganesh
- Administrator
- Registered: 2005-06-28
- Posts: 48,402
Re: Elementary Physics
Exactly, p represents momentum. (I believe the lower case is used always).
Dimension : MLT-¹
m is mass, always. Only when expressed as a unit, it denotes metres.
It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.
Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.
Offline
Pages: 1