Answer:
A) t = 0.55 s
B) x = 24.8 m
Explanation:
A) We can find the time at which the ball will be in the air using the following equation:
Where:
is the final height= 0
is the initial height= 1.5 m
is the component of the initial speed in the vertical direction = 0 m/s
t: is the time =?
g: is the gravity = 9.81 m/s²

By solving the above equation for t we have:
Hence, the ball will stay 0.55 seconds in the air.
B) We can find the distance traveled by the ball as follows:

Where:
a: is the acceleration in the horizontal direction = 0
is the final position =?
is the initial position = 0
is the component of the initial speed in the horizontal direction = 45 m/s


Therefore, the ball will travel 24.8 meters.
I hope it helps you!
Answer:
Explanation:
The negative only matters reallly if you are dealing with a 2d system. I could even define down as positive and up as negative. However, usually you are taught that down is negative. It really doesn't matter because a force is a force. It is only given a direction relative to another force or vector direction.
Answer:
The racetrack is 996.7 meters long
Explanation:
Convert 251km/h to km/s (kilometers per second)
3600 seconds in an hour, so:
251/3600 = 0.0697km/s
Convert km/s to m/s (meters per second)
1000 meters in a kilometer, so:
0.0697*1000 = 69.7m/s
Find length of racetrack:
69.7m/s*14.3s = 996.7m
If the racer travels 69.7 meters in one second and it takes 14.3 seconds to complete a lap, the racetrack is 996.7 meters long.
In my opinion, the third answer makes the most sense