B. Wrap more coils of wire around the nail
Increasing the number of coils in an electromagnet increases the strength of the magnetic field.
Given
The projectile is in air for a time of t=8 sec
To find
The time it takes to reach the highest point
Explanation
A projectile moves up to the highest point and then again moves down following a parabolic path.
So it will reach the highest point at a time half the time it requires to follow teh parabolic path.
The time taken to reach the highest point is 4 sec
Conclusion
The time taken is 4 sec.
plane is flying at an altitude of 70 m
now if an object is dropped from it then time taken by object to drop on ground will be given as

here initial speed in vertical direction must be zero as plane is moving horizontal
given that
y = 70 m
a = 9.8 m/s^2


now since the plane is moving horizontally with speed v = 44 m/s
so the horizontal distance moved by the object will be



so the distance moved by the box is 166.3 m
Out of the choices given, igniting the gas-air mixture supplies the heat for the hot reservoir in a car's engine. The correct answer is C.
No. Mechanical energy is not conserved. There's quite a bit of friction on the slide. So some of the potential energy is lost to heat on the way down, and the child arrives at the bottom with hot pants and less kinetic energy than you might expect.