Answer:
the change in momentum = Force x change in time
The wave speed completely depends on the characteristics and properties of the medium . . . physical properties for mechanical waves, electrical properties for electromagnedtic waves.
So if you want to change the speed of a wave, you have to change the medium . . . shoot it through some different kind of stuff. <em>(B) </em>
Answer:
Acceleration of the crate is 0.362 m/s^2.
Explanation:
Given:
Mass of the box, m = 40 kg
Applied force, F = 15 N
Angle at which the force is applied, 
= 15°
We have to find the magnitude of the acceleration.
Let the acceleration be "a".
FBD is attached with where we can see the horizontal and vertical component of force.
⇒ 
and ⇒ 
⇒ 
⇒ 
⇒ Applying concept of forces.
⇒ 
⇒ 
⇒ 
<em> ...Newtons second law Fnet = ma</em>
⇒ 
⇒ Plugging the values.
⇒ 
<em>...f is the friction which is zero here.</em>
⇒ 
⇒ 
Magnitude of the acceleration of the crate is 0.362 m/s^2.
Answer:
3.80 m/s
Explanation:
Solution: From the question we have:
A 2.10 x 10^3 kg car starts from rest at the top of a 5.0 m long driveway that is sloped at 20 degrees with the horizontal.
average friction force of 4.0 x 10^3 N impedes the motion
To find out: find the speed of the car at the bottom of the driveway.
=>h = 5×sin20 = 1.71 m.
PE = mgh = 2100×9.8×1.71 = 35,192 J.
KE = PE-work done by frictional force
KE=PE-4000×5
0.5mV^2 = 35192 - 4000×5
1050V^2 = 15,192
V^2 = 14.47
V = 3.80 m/s.
