Answer:
I couldn't find options for your question online, but I can give you an explanation so you can choose the correct option.
Explanation:
A spark knock is a form of unpredictable behavior that occurs in combustion, that is, in the chemical reaction that occurs between oxygen and an oxidizable material. Such combustion is usually manifested by incandescence or flame.
The spark knock is a detonation that occurs when there is a lot of pressure in the fuel.
<u>Some situations in which this can happen are:
</u>
- Engine overloaded.
- Maximum pressure in the cylinders.
- Engine overheated.
- Overheated air.
- Long and excessive engine ignition timing.
- Spark plug at high temperatures.
Answer:
S = 0.5 km
velocity of motorist = 42.857 km/h
Explanation:
given data
speed = 70 km/h
accelerates uniformly = 90 km/h
time = 8 s
overtakes motorist = 42 s
solution
we know initial velocity u1 of police = 0
final velocity u2 = 90 km/h = 25 mps
we apply here equation of motion
u2 = u1 + at
so acceleration a will be
a =
a = 3.125 m/s²
so
distance will be
S1 = 0.5 × a × t²
S1 = 100 m = 0.1 km
and
S2 = u2 × t
S2 = 25 × 16
S2 = 400 m = 0.4 km
so total distance travel by police
S = S1 + S2
S = 0.1 + 0.4
S = 0.5 km
and
when motorist travel with uniform velocity
than total time = 42 s
so velocity of motorist will be
velocity of motorist = 
velocity of motorist =
velocity of motorist = 42.857 km/h