An ice skater with a mass of 50 kg is gliding across the ice at a speed of 8 m/s when her friend comes up from behind and gives her a push, causing her speed to increase to 12 m/s. How much work did the friend do on the skater?

• 10 J
• 20 J
• 100 J
• 2000 J

here we know that ball will drop down by total distance 3.2 m

so here we know that

now using kinematics

now in the same time it will cover horizontal distance of 0.75 m

so speed of the ball will be

the closer the planet is to the sun, the larger the gravity

electric field is a function of 1/r^2

yes, the force per unit charge for a point charge is inverse square law.