D.
50 mph - 30 mph= 20 mph net velocity
change.
20mph/3600 seconds/hour= .00555 MPS
.0055 miles per second
40 seconds to complete the change
.0055/40= .000138
Take the derivative to find the velocity of the object:

The object stops when
:

so the answer is E.
Answer:
Heat required = mass× latent heat Q = 0.15 × 871 ×
Answer:20 minutes
Explanation:
06:58am - 06:38am =20 minutes