M1 question

Hi, I was wondering if anybody could help me with this question. I am resitting M1 and I'm slightly confused:

A particle P of weight 8N rests on a horizontal surface. A horizontal force of magnitude 3N acts on P, and P is in limiting equilibrium.

i) Calculate the coefficient of friction between P and the surface - [I've managed to do this by resolving vertically and horizontally. I obtained 3/8].

ii) Find the magnitude and direction of the contact force exerted by the surface on P.

I'm confused by part 2. This is because If I'm correct, they want me to calculate the reaction force. But haven't I already done that for the first part of the question?

Thank you in advance!

Reply 1

Puddles the Monkey

21

Original post by Incubator

Hi, I was wondering if anybody could help me with this question. I am resitting M1 and I'm slightly confused:

A particle P of weight 8N rests on a horizontal surface. A horizontal force of magnitude 3N acts on P, and P is in limiting equilibrium.

i) Calculate the coefficient of friction between P and the surface - [I've managed to do this by resolving vertically and horizontally. I obtained 3/8].

ii) Find the magnitude and direction of the contact force exerted by the surface on P.

I'm confused by part 2. This is because If I'm correct, they want me to calculate the reaction force. But haven't I already done that for the first part of the question?

Thank you in advance!

Heya, I'm going to put this in the Maths forum for you as you should get more responses there.You should also check out the forum to see if there's any other threads there which might be helpful to you!http://www.thestudentroom.co.uk/forumdisplay.php?f=38

Reply 2

brianeverit

9

Original post by Incubator

Hi, I was wondering if anybody could help me with this question. I am resitting M1 and I'm slightly confused:

A particle P of weight 8N rests on a horizontal surface. A horizontal force of magnitude 3N acts on P, and P is in limiting equilibrium.

i) Calculate the coefficient of friction between P and the surface - [I've managed to do this by resolving vertically and horizontally. I obtained 3/8].

ii) Find the magnitude and direction of the contact force exerted by the surface on P.

I'm confused by part 2. This is because If I'm correct, they want me to calculate the reaction force. But haven't I already done that for the first part of the question?

Thank you in advance!

You are being asked for the resultant of the friction force and the normal reaction.

Reply 3

tory88

18

Original post by Incubator

Hi, I was wondering if anybody could help me with this question. I am resitting M1 and I'm slightly confused:

A particle P of weight 8N rests on a horizontal surface. A horizontal force of magnitude 3N acts on P, and P is in limiting equilibrium.

i) Calculate the coefficient of friction between P and the surface - [I've managed to do this by resolving vertically and horizontally. I obtained 3/8].

ii) Find the magnitude and direction of the contact force exerted by the surface on P.

I'm confused by part 2. This is because If I'm correct, they want me to calculate the reaction force. But haven't I already done that for the first part of the question?

Thank you in advance!

The reaction force (also called the normal reaction) is what stops the particle falling through the table. From this information alone you know what direction it points in; add this arrow to your diagram and resolve to find its magnitude.

If you're still stuck, quote me (attach a force diagram if possible)

Reply 4

Incubator

OP

20

Original post by brianeverit

You are being asked for the resultant of the friction force and the normal reaction.

OOOOHHHH! Thank you!

Reply 5

ZolaCFC25

18

Original post by Incubator

Hi, I was wondering if anybody could help me with this question. I am resitting M1 and I'm slightly confused:

A particle P of weight 8N rests on a horizontal surface. A horizontal force of magnitude 3N acts on P, and P is in limiting equilibrium.

i) Calculate the coefficient of friction between P and the surface - [I've managed to do this by resolving vertically and horizontally. I obtained 3/8].

ii) Find the magnitude and direction of the contact force exerted by the surface on P.

I'm confused by part 2. This is because If I'm correct, they want me to calculate the reaction force. But haven't I already done that for the first part of the question?

Thank you in advance!

Oh, thought this thread was about the motorway haha. Hate those bloody 50mph average speed checks to and fro uni.