# physics

Two forces, of magnitudes F1= 80.0N and F2= 50.0N, act in opposite directions on a block, which sits atop a frictionless surface, as shown in the figure. Initially, the center of the block is at position x1= -3.00cm. At some later time, the block has moved to the right, and its center is at a new position, x2= 2.00cm.
a)Find the work W1 done on the block by the force of magnitude F1= 80.0N as the block moves from x1= -3.00 cm to x2= 2.00 cm
b)Find the work done by the force of magnitude F2 = 50.0 N as the block moves from x1= -3.00 Ncm to x2= 2.00cm.
c)What is the net work Wnet done on the block by the two forces?
d)Determine the change in the kinetic energy (Kf-Ki) of the block as it moves from x1= -3.00 cm to x2= 2.00 cm.

1. 👍 0
2. 👎 0
3. 👁 3,754
1. You don't say which force acts in the direction of motion and which does not. Presumably F1, which is larger, is along the direction of motion. Otherwise the block would move backwards.

One force will do positive work and the other, negative work.

For (d) Kf - Ki equals the net work done (since there is no friction)

Do not expect step by step solutions here. We prefer to provide quidelines so you can do the work yourself.

1. 👍 0
2. 👎 0
2. a) F_1=80*(0.03+0.02)
b) F_2=50*(0.03+0.02)
d) same as part c

1. 👍 1
2. 👎 0
3. a) 4

1. 👍 0
2. 👎 0

## Similar Questions

1. ### Physics - electrons/protons

If you place a free electron and a free proton in the same electric field, how do the forces acting on them compare? How do their accelerations compare? Their directions of travel? My answer: Direction of travel: The proton and

asked by Mary on October 4, 2009
2. ### Physics

Two ice skaters have masses m1 and m2 and are initially stationary. Their skates are identical. They push against one another, as shown below, and move in opposite directions with different speeds. While they are pushing against

asked by Will on April 1, 2008
3. ### Physics

A body is under action of 2 forces ,7N and 10N . Find the resultant of the 2 forces, if (a)the forces are parallel and act in the same direction (b) the forces are parallel and act in the opposite direction (c) the forces are

asked by Esther on September 22, 2019
4. ### Math

Three forces with magnitudes of 70 pounds, 40 pounds, and 60 pounds act on an object at angles of -30 degrees, 45 degrees, and 135 degrees, respectively, with the positive x-axis. Find the direction and manitude of the resultant

asked by Hannah on March 31, 2010
5. ### math/physics

Forces with magnitudes of 2000 newtons and 900 newtons act on the machine part at angles of 30 degrees and -45 degrees respectively, with the x-axis. Find the direction and magnitude of the resultant of these forces.

asked by Cydni on April 10, 2012
1. ### Physics

Three forces are exerted on an object placed on a tilted floor. Forces are vectors. The three forces are directed as shown in the figure. If the forces have magnitudes F1 = 2.0 N, F2 = 17.0 N and F3 = 15.0 N, where N is the

asked by Eric on September 11, 2015
2. ### science

Two forces, of magnitudes F_1 = 85.0 N and F_2 = 45.0 N, act in opposite directions on a block, which sits atop a frictionless surface, as shown in the figure. Initially, the center of the block is at position x_i = -4.00 cm. At

asked by BRIJ on November 23, 2010
3. ### math

two forces of magnitudes 7N and 9N act at an angle alpha such that sin alpha=0.4. Find the magnitudes of the two possible resultants

asked by georgina on May 8, 2014
4. ### pre calculus

Forces with magnitudes of 250 pounds and 130pounds act on an object at angles 45degrees and -60degrees respectively with the positive axis. Find the direction and magnitude of the resultant of these forces.

asked by Anonymous on November 26, 2016
5. ### Physics

Two horizontal forces F1 and F2 act on a 1.7 kg disk that slides over frictionless ice, on which an xy coordinate system is laid out. Force F1 is in the negative direction of the x axis and has a magnitude of 3.0 N. Force F2 has a

asked by Leo on March 6, 2012