3. A car waits at a red light for a few seconds, and then accelerates straight ahead to 54 km/h in 3.1 s and then cruises at a constant speed for 75 m. The road is straight. Find the total
distance and time travelled

In the first 3.1 s, the car accelerates with acceleration a from rest to a speed of 54 km/h = 15 m/s, so its acceleration is

15 m/s = a (3.1 s)

a = (15 m/s) / (3.1 s)

a ≈ 4.8 m/s²

So in this time, it travels a distance of

x = 1/2 (4.8 m/s²) (3.1 s)²

x = 23.25 m

For the remaining time, it moves at a constant 15 m/s, covering a distance x of

x = (15 m/s) t

for until it moves 75 m, which takes

75 m = (15 m/s) t

t = (75 m) / (15 m/s)

t = 5 s

So, the car travels a total distance of 98.25 m in 8.1 s.

answer: d. a cme increases the amount of energy in the solar wind

explanation:

coronal mass ejections, also called cmes, are large clouds of plasma and magnetic field that erupt from the sun. only when the cloud is aimed at earth will the cme hit earth and therefore cause impacts. high-speed solar wind streams come from areas on the sun known as coronal holes.