# RE: PHYSICS

posted by .

A stationary block explodes into two pieces L and R that slide across a frictionless floor and then into regions with friction, where they stop. Piece L, with a mass of 2.0 kg, encounters a coefficient of kinetic friction µL = 0.40 and slides to a stop in distance dL = 0.15 m. Piece R encounters a coefficient of kinetic friction µR = 0.50 and slides to a stop in distance dR = 0.20 m. What was the mass of the original block?

* Physics - bobpursley, Sunday, February 25, 2007 at 5:24pm

the momentum of L and R are equal.

energyL= mu*mg*distance
then solve for velocity L (KE=energy)

knowing velocityL, you can use momentum to find veloicty R.

* Physics - COFFEE, Sunday, February 25, 2007 at 11:29pm

I did:

energyL = mu*mg*distance
energyL = (.4)(2)(9.8)(.15)
energyL = 1.176

Then,

KE = 1/2mv^2
1.176 = 1/2(2)v^2
v = 1.08 m/s

Then which equation do I use???

So the momentum sum is zero.
1.08*2+Vr*massR=0
You have to solve for Vr the same way.
1/2 Mr*Vr^2= Mur*Mr*g*Dr notice the Mr divide out, so solve for Vr. Put that in the equation
1.08*2+Vr*massR=0
solve for mass r.
Then total mass is massR+2

## Similar Questions

1. ### Physics

A stationary block explodes into two pieces L and R that slide across a frictionless floor and then into regions with friction, where they stop. Piece L, with a mass of 2.0 kg, encounters a coefficient of kinetic friction µL = 0.40 …
2. ### Re: PHYSICS

A stationary block explodes into two pieces L and R that slide across a frictionless floor and then into regions with friction, where they stop. Piece L, with a mass of 2.0 kg, encounters a coefficient of kinetic friction µL = 0.40 …
3. ### physics

In Figure block 1 of mass m1 slides from rest along a frictionless ramp from height h = 3.10 m and then collides with stationary block 2, which has mass m2 = 5.00m1. After the collision, block 2 slides into a region where the coefficient …
4. ### physics

In the figure, a stationary block explodes into two pieces L and R that slide across a frictionless floor and then into regions with friction, where they stop. Piece L, with a mass of 2.0 kg, encounters a coefficient of kinetic friction …
5. ### ap physics

Starting from rest, a 10.2 kg block slides 2.90 m down a frictionless ramp (inclined at 30.0° from the floor) to the bottom. The block then slides an additional 4.80 m along the floor before coming to a stop. Determine the coefficient …
6. ### Physics

Block 1, with mass m1 and speed 4.5 m/s, slides along an x axis on a frictionless floor and then undergoes a one-dimensional elastic collision with stationary block 2, with mass m2 = 0.41m1. The two blocks then slide into a region …
7. ### Physics

Block 1 of mass m1 slides from rest along a frictionless ramp from height h and then collides with stationary block 2, which has mass m2 = 3m1. After the collision, block 2 slides into a region where the coefficient of kinetic friction …
8. ### physics

In the figure, block 1 of mass m1 slides from rest along a frictionless ramp from height h = 2.8 m and then collides with stationary block 2, which has mass m2 = 2m1. After the collision, block 2 slides into a region where the coefficient …
9. ### Physics MCAT, Help please

A box of mass m = 6kg slides with speed v = 4 m/s across a frictionless floor. It suddenly explodes into two pieces. One piece, with mass m1 = 2kg moves in the same direction with speed v1 = 8m/s. Find the velocity of the second piece. …
10. ### physics

A block of wood with a mass of 1300g is sitting on a horizontal tabletop. The coefficient of kinetic friction between the block and table is µk=0.74.A rifle bullet with a mass of 39g is fired horizontally into the block at a sped …

More Similar Questions