A 4 kg box is next to a 2 kg box on a rough horizontal surface. The coefficient of static friction is 0.3 and coefficient of kinetic friction is 0.2. a) What minimum horizontal force is needed to be applied to the 4 kg box in order to start to move both boxes horizontally? b) What is the acceleration of the boxes when they are moving by this force? c) Find the contact force between the boxes.

it's a b and

80cm/s.

24cm/s.

53.3cm/s.

the aurora is formed when charged particles emitted from the sun during a solar flare penetrate the earth's magnetic shield and collide with atoms and molecules in our atmosphere. these collisions result in countless little bursts of light, called photons, which make up the aurora.

auroras are generated by charged solar particles hitting molecules in earth's atmosphere. this usually happens in high latitudes, because our planet’s magnetic field tends to funnel these particles toward the poles. that’s why it can be experienced in northern ohio.