Arace car accelerates uniformly at 11.3 m/s2. if the race car starts from rest how fast will it
be going after 6.7 seconds.

75.71 m/s

Explanation:

From equation of motion, acceleration is given by

where v is the final velocity, u is the initial velocity and t is time taken.

Making v the subject of the above formula

v=at+u

Substituting 6.7 s for time, t and 11.3 for a and taking u as zero since it starts from rest

v=11.3*6.7=75.71 m/s

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.