Answer:
the work done by the 30N force is 4156.92 J.
For this problem, they don´t ask you to determine the work of the total force applied in the block. They only want the work done for the force of 30N, with an angle of 30º respectively of the displacement and a traveled distance of 160m. So:
W=F·s·cos(α)=30N·160m·cos(30º)=4156.92J
k e is energy of movement. When thing solidifies, atoms stop moving ke is less.
Answer:
Option D
Explanation:
The work done can be given by the mechanical energy used to do work, i.e., Kinetic energy and potential energy provided to do the work.
In all the cases, except option D, the energy provided to do the useful work is not zero and hence work done is not zero.
In option D, the box is being pulled with constant velocity, making the acceleration zero and thus Kinetic energy of the system is zero. Hence work done in this case is zero.
Answer:
The correct answer is "1080 W".
Explanation:
Given:
Current,
I = 9.0 A
Potential difference,
V = 120 volt
As we know,
⇒ 
On substituting the values, we get
⇒ 
⇒ 
Answer: a) 10.4km
b) 0.62h
C) 17km/h
d) 9.1km/h
Explanation:
A) suppose you move in the positive direction of an x axis, from a first position of x1 = 0 to a second position of x2 at the station. That second position must be at x2 = 8.4 km + 2.0 km = 10.4 km.
B) time interval Dtwlk (= 0.50 h), but we don't know the driving time interval Dt/dr. However, we know that for the drive the displacement Dx/dr is 8.4 km and the average velocity vavg,dr is 70 km/h.
This average velocity is the ratio of the displacement for the drive to the time interval for the drive:
dv = dx/ dt
dt = dx/dv = 8.4/70 = 0.12h
t = ti + two
t = 0.12 + 0.50 = 0.62h
C) avg speed for the entire trip is the ratio of the displacement of 10.4 km for the entire trip to the time interval of 0.62 h for the entire trip.
Avg v = distance/time
10.4/0.62 = 16.8km/h
D) average speed is the ratio of the total distance you move to the total time interval you take to make that move. The total distance is 8.4 km + 2.0 km + 2.0 km = 12.4 km. The total time interval is 0.12 h + 0.50 h + 0.75 h = 1.37 h.
Avg speed = 12.4/1.37 = 9.1km/h
