<u>Answer:</u>
Force = 20N
acceleration (a) = 1.5 m/s²
Mass of object (m) = ?
<u>From Newtons II law</u>
<em> F = m. a N</em>
m = F/a
m = 20/1.5
<em> m = 13.34 Kg</em>
<em>Mass of an object is 13.34 Kg</em>
The train is moving at 50 m/s and Emma is walking down the aisle with 1 m/s speed in the same direction of train. The relative velocity of Emma with respect to other passengers pf the train would be 1 m/s. This is because, the train is not moving relative to them and only emma is moving at 1 m/s. If a person observes from outside, Emma would have (50 +1) m/s = 51 m/s velocity.
relative velocity when two objects are moving in same direction as oberved from outside observer:

relative velocity when two objects are moving in the opposite directionas oberved from outside observer:

Volume of tea V = 2.0L = 2000 mL density d = 1.01 g/ mL mass of tea m = V * d = 2000mL * 1.01g/mL = 2020 gWhen we assume that the tea was initially at 72, the final temperature of the tea in F is 91.
The answer in this question is B. 91
I think the answer is b. easy to digest.
C. and D. are chemical properties,