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I've been up all today doing homework for a science class and I have just 3 more problems could someone please explain them to me...not just give me the answers maybe tell me the formula to use. I dont know them because I have tried the acceleration formula

The first one is:
It takes 40 sec for a car at rest to reach a velocity of 50 m/s. What is the car's acceleration?
A. 0 m/s
B. 1.25 m/s
C. 1.25 m/s2(squared)
D. 50 m/s
E. 50 m/s2(squared)

The 2nd question is:
A car that starts from rest has a constant acceleration of 4m/s2(squared). In the first 3s the car travels
A. 6m
B. 12m
C. 18m
D. 172m

And last but not least
When a net force of 1N acts on a 1kg body, the body receives
A. A speed of 1 m/s
B. An acceleration of 0.1 m/s2(squared)
C. An acceleration of 1 m/s2(squared)
D. An acceleration of 9.8 m/s2(squared)

Thank you in advance for your help.

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