A worker pushed a 30.0 kg block 6.50 m along a level floor at constant speed with a force directed 30.0° below the horizontal. If the coefficient of kinetic friction between block and floor was 0.190, what were (a) the work done by the worker's force and (b) the increase in thermal energy of the block-floor system?

The work done by worker's force is same as thermal energy 327.2 J

Explanation:

Given :

Mass of block Kg

Displacement m

Angle 30°

Coefficient of kinetic friction

(A)

The work done by the worker's

Here force is given by,

Where

    N

So work done by,

J

(B)

The thermal energy of the block floor system is,

Therefore, the work done by worker's force is same as thermal energy 327.2 J

i just did an experiment like this in my science class. also the answer is yes, it will get separated because they are two opposites meaning if they are opposite they can not attract.

hope this .!

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s