Physics, 19.02.2020 05:58 cdfvghjk

12.0-kg block is pushed across a rough horizontal surface by a force that is angled 30.0◦below thehorizontal. The magnitude of the force is 75.0 N and the acceleration of the block as it is pushed is 3.20m/s2. What is the magnitude of the contact force exerted on the block by the surface?

Answers: 1

Show answers

Answers

Answer from: drice517

26.55N

Explanation:

Newton's second law of motion states that the effective/resultant (∑F) force acting on a body is the product of the mass (m) of the body and the acceleration (a) caused by this force, as follows;

∑F = m x a

From the question, the two forces acting on the body are;

(i) the force (say F) of push which is 75.0N inclined at 30° below the horizontal. Since this force is inclined at an angle, it means that it has two components - the vertical ( $F_{Y}$ ) and the horizontal ( $F_{X}$ ) - and are calculated as follows;

=> $F_{Y}$ = F sin θ

Note: That the vertical component, $F_{Y}$ , of the force will be negative since it is inclined at an angle below the horizontal

∴ $F_{Y}$ = -75.0 sin 30° = - 37.5N

Also,

=> $F_{X}$ = F cos θ

∴ $F_{X}$ = 75.0 cos 30° = 64.95N

Since the motion of the block is on the horizontal, the horizontal component ( $F_{X}$ = 64.95N) is sufficient to solve the problem at hand and will be used.

(ii) the contact force exerted on the block by the surface. This force is due to friction and is called the frictional force ( $F_{R}$ ) and it acts to oppose the force of push on the block. Therefore, it is going to have a negative sign to show that it acts in a direction opposite to that of the force of push.

Therefore, the resultant/effective force (∑F) is found by summing the horizontal component of the force of push ( $F_{X}$ ) and the frictional force ( $F_{R}$ ) which also acts in the horizontal, as follows;

∑F = $F_{X}$ - $F_{R}$

∑F = 64.95 - $F_{R}$

Now, substitute the value of ∑F into equation (i) as follows;

64.95 - $F_{R}$ = m x a ----------------------(ii)

Where;

m = mass of the block = 12.0kg

a = acceleration of the block = 3.20m/s²

Substitute these values into equation (ii) as follows;

64.95 - $F_{R}$ = 12.0 x 3.20

64.95 - $F_{R}$ = 38.4

Solve for $F_{R}$ ;

$F_{R}$ = 64.95 - 38.4

$F_{R}$ = 26.55N

Therefore, the contact force exerted on the block by the surface is 26.55N

Answer from: Quest

luster is not a good characteristic to use by itself because luster is the property of minerals that indicates how much the surface of a mineral reflects light. the luster of a mineral is affected by the brilliance of the light used to observe the mineral surface.

Answer from: Quest

Gas will most likely fill the container

Another question on Physics

Physics, 21.06.2019 15:00

The equation that describes a transverse wave on a string is y = (0.0120 m)sin[(927 rad/s)t - (3.00 rad/m)x] where y is the displacement of a string particle and x is the position of the particle on the string. the wave is traveling in the +x direction. what is the speed v of the wave?

Answers: 1

Answer

Physics, 22.06.2019 04:50

Two technicians are discussing a resistance measurement between the can-h and can-l wires. technician a says this measurement should be done with the ignition switch in the "run" position. technician b states that a measurement of 0 ohms indicates an open in the network. which technician is correct?

Answers: 1

Answer

Physics, 22.06.2019 16:00

What is the measure of how much matter is in an object and that can be measured using a balance? a. height b. volume c. weight d. mass

Answers: 1

Answer

Physics, 22.06.2019 21:00

On a mild saturday morning while people are working inside, the furnace keeps the temperature inside the building at 23degreesc. at noon the furnace is turned off, and the people go home. the temperature outside is a constant 16degreesc for the rest of the afternoon. if the time constant for the building is 3 hr, when will the temperature inside the building reach 18degreesc? if some windows are left open and the time constant drops to 2 hr, when will the temperature inside reach 18degreesc?

Answers: 3

Answer

You know the right answer?

12.0-kg block is pushed across a rough horizontal surface by a force that is angled 30.0◦below theho...

Questions