The car is initially traveling north at 17.7 m/s, and after 12 s, its velocity is 14.1 m/s, still due north. This means that the direction of the car has not changed, so we can already say that the direction of the acceleration is north (if the magnitude of the acceleration is positive) or south (if the magnitude of the acceleration is negative).
To find the magnitude of the average acceleration, we must calculate the ratio between the change in velocity and the time taken:

Since the acceleration is negative, it means it is in the opposite direction to the motion of the car, therefore south. Therefore, the correct answer is
b) 0.30 m/s2, south
Answer:
The maximum mass of water that could be produced by the chemical reaction is 10.1 g
Explanation:
The equation of reaction involves the combustion of 2 moles of hexane (C6H14) with 19 moles of oxygen (O2) to produce 12 moles of carbon dioxide (CO2) and 14 moles of water (H2O)
From the equation of reaction above,
2 moles of C6H14 (172 g) produced 14 moles of H2O (252 g)
6.9 g of C6H14 would produce (6.9×252/172) = 10.1 g of water (to 3 significant figures)
Also, from the equation of reaction,
19 moles of O2 (608 g) produced 14 moles of H2O (252 g)
17.3 g of O2 would produce (17.3×252/608) = 7.17 g of water (to 3 significant figures)
Maximum mass of water produced = 10.1 g
Answer:
Clock on the satellite is slower than the one present on the earth = 29.376 s
Given:
Distance of satellite from the surface, d = 250 km
Explanation:
Here, the satellite orbits the earth in circular motion, thus the necessary centripetal force is provided by the gravitation force and is given by:

where
v = velocity of the satellite
R = radius of the earth = 6350 km = 6350000 m
G = gravitational constant = 
M = mass of earth = 
Therefore, the above eqn can be written as:

Now, for relativistic effects:

Now,
r = R + 250

Ratio of rate of satellite clock to surface clock:

Clock on the satellite is slower than the one present on the earth:
