Example 3.6 P 55 A child pushes a sled across a frozen pond with a horizontal force
of 20 N. neglecting the friction
If the sled accelerated with 0.5 ms 2, what is its mass?
Another child with 60 kg mass sit on the sled. What is the
acceleration will be produced by the same force ?

An electron moves with a constant horizontal velocity of 3.0 × 106 m/s and no initial vertical velocity as it enters a deflector inside a tv tube. the electron strikes the screen after traveling 26 cm horizontally and 19 cm vertically upward with no horizontal acceleration. what is the constant vertical acceleration provided by the deflector? (the effects of gravity can be ignored.)