To 语者, 

(a) When a charged rod is brought near the metal sphere without touching it, some of the positive and negative charges in the sphere are...

Like charges repel and unlike charges attract each other. A new technology based on the electric force may revolutionise the way books...

The total mechanical energy (E = KE + PE) of an object remains constant as the object moves, provided that the net work done by external...

A person whose true weight is 700 N steps on the scale. If the elevator is at rest or moving with a constant velocity (either upward or...

The unit mm Hg (millimeter of mercury) is often called the torr in honor of Torricelli. The terms torr and mm Hg are used interchangeably...

Definition of Inertia and Mass Inertia is the natural tendency of an object to remain at rest or in motion at a constant velocity. The...

V PT = velocity of the Passenger relative to the Train = + 2.0 m/s V TG = velocity of the Train relative to the Ground = + 9.0 m/s V PG =...

The figure above shows an airplane moving horizontally with a constant velocity of + 115 m/s at an altitude of 1050 m. The directions to...

A motorcycle ride consists of two segments, as shown in the figure blow. During segment 1, the motorcycle starts from rest, has an...

A jet is taking off from the deck of an aircraft carrier, as the figure shows. Starting from rest, the jet is catapulted with a constant...

上面的表格直观地体现了密度在不同状态的物质中的区别，大致上我们可以总结为固体密度大于液体密度大于气体密度。 水分子在固体ice，液体water和气体gas中明显体现出了分子间的密度差异性。通过图解的方式会让我们对于抽象的物理化学原理能够有更深刻的理解。 #Chemistry...

关于温度的换算是一个非常基本的化学和物理常识： Temperature (Kelvin) = temperature (Celsius) + 273.15 大家发现Kelvin和实际温度的关系，也是比较容易理解的，接下来我们要强调下Fahrenheit和Celsius之间的...

我们推荐一种国际流行的单位换算方法，例如换算centimetre 到 inch： 65 cm = ? in 解法如下： 65 cm * (1) ＝ 65 cm * (1 in/2.54 cm) = 25.59 in 也就是说每换算一次单位就需要乘以一次(1)，这样一定会保证...