Question

answer me plzzz I will mark brainliest and this is 100 point question​

Answer 1

1.

u= initial velocity= 80 km/h = 22.2 m/s

v= final velocity = 60 km/h = 16.7 m/s

t= time = 5 s

a= acceleration = ?

a=v-u/t

a= 16.7-22.2/5

a= -5.5/5

Therefore, a=-1.1 $m/s^{2}$

2.

The train started from a railway station, so initial velocity of train, u = 0

Final velocity of train, v = 40 kmph  

Final velocity, v = 40 × 5/18 = 11.11 m/s

Assuming uniform acceleration of ‘a’ m/second square

Time taken by train to get it's final velocity, t = 10 minutes = 600 seconds

Using first equation of motion,

V = u + at

11.11 = 0 + a×600

a = 11.11/600 = 0.0185 m/second square.

So, required acceleration , a = 0.0185 $m/s^{2}$

3.

Average speed=total distance/total time

d=distance travelled at 30m/s and distance travelled at 40m/s … same distance

time=distance/speed

time at 30m/s =d/30

time at 40 m/s=d/40

total time=d/30 + d/40= 7d/120

average speed= (d+d)/(7d/120)= 240/7=34.2857 m/s

It is not the average of the speeds because he spends more time at 30 m/s then at 40 m/s

4.

Distance covered in half an hour at 30km/hr = s×t = 30×1/2=15km.

Distance coveted in 1hr at 25km/hr= s×t= 25×1 =25km.

Distance covered in 2 hrs at 40km/hr=s×t= 40×2=80km

Therefore, total distance covered= 15+25+80=120km

Total time taken= 3hrs and 30 mins=7/2 hrs.

Therefore, average speed=total distance covered/total time taken = 120×2/7 = 34.28km/hr

5.

Answer 2

Explanation:

Aloha !

1)u=22.2

v=16.7

We know that,

a=v-u/t

=16.7-22.2/5

=-5.5/5

=-1.1

Thank you.

@ Twilight Astro ✌️☺️♥️ you