Để thu được ảnh thật của một vật sáng qua thấu kính có độ lớn bằng vật thì vật phải có ở cách thấu kính một khoảng bằng

correct it is c.) b b

we need to know the time interval during which the force acts. impulse of force = momentum change

f=ma newton

f=100x2.5=250n

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.