Stepping on a can is a physical change because there is no chemistry behind this. Someone is physically breaking or deforming the can. There are no chemicals or anything touching the can. The foot smashing is physical.

4 0

2 years ago

Describe a situation in which an object's speed is constant but its velocity is changing.

Olegator [25]

1) If the object changes directions with the same speed, it will be changing its velocity, because velocity is a vector, which depends on both magnitude and direction. Speed is just magnitude regardless of direction.

2) Rotational motion.

5 0

2 years ago

A positron is an elementary particle identical to an electron except that its charge is . An electron and a positron can rotate

denis23 [38]

Explanation:

According to the energy conservation,

$F_{centripetal} = F_{electric}$

$\frac{mv^{2}}{r} = \frac{kq^{2}}{d^{2}}$

$v^{2} = \frac{kq^{2}r}{d^{2}m}$

= $\frac{9 \times 10^{9} N.m^{2}/C^{2} \times 1.6 \times 10^{-19} C \times 0.75 \times 10^{-9} m}{(1.50 \times 10^{-9}m)^{2} \times 9.11 \times 10^{-31} kg}$