Answer:
v = 11 m/s is her final speed
Explanation:
work done by gravity = m g Δh = 40×9.8×10 = 3920 Joules
Work done by friction = - force×distance = - 20×100 = - 2000 Joules
[minus sign because friction force is opposite to the direction of motion]
Initial K.E. = (1/2) m u^2 = (1/2) × 40 × 5^2 = 500 Joules
Now, by work energy theorem
Work done = change in kinetic energy.
Final K.E. = initial K.E. + total work = 500 + 3920 - 2000 = 2420 Joules
Now, Final K.E. = (1/2) m v^2 [final speed being v= speed at the bottom]
⇒ 2420 = (1/2)×40×v^2
⇒ 121 = v^ 2
v = 11 m/s is her final speed
I can't decide between A and B, but B seems more likely to me. Even though the molecules don't look like they're moving, the area of contact is slightly more compressed.
-4.4 ft/s^2
Explanation:
Final Velocity= 35 mph
Starting Velocity= 50 mph
Elapsed Time= 5 seconds
When plugged into formula for Acceleration it is this
Resistance= Potential Difference/Current
10 Ohm= PD/ 5A
PD= 10 Ohm × 5A
PD=50
Therefore, Potential Difference is B. 50 V
We know that the centripetal acceleration is zero, since the summation of forces is the mass times the acceleration in the x- component.
