91影视

A Force causes an object to accelerate. The acceleration $a$acting on an object is directly proportional to the force $F$acting on the object and inversely proportional to the mass $m$of the object.

Two rubber bands produce an acceleration of $1.2\text{m}/{\text{s}}^2$. The numbers of bands that are pulling the object are doubled. Which means the applied force gets doubled. Hence, for a given mass of the object, the acceleration produced by four bands is also doubled. So,

$\begin{array}{l}a=2\left(1.2\text{m}/{\text{s}}^2\right)\\ =2.4\text{m}/{\text{s}}^2\end{array}$

Therefore, the acceleration of the object when it is pulled with four bands is$2.4\text{m}/{\text{s}}^2$ .

If two objects of identical masses are glued together, the net mass of the system increases by two times. hence the acceleration reduced by a factor of 2 . Thus, the acceleration of the two objects that are joined together is,

$\begin{array}{l}{a}^{\text{'}}=\frac{a}{2}\\ =\frac{1.2\text{m}/{\text{s}}^2}{2}\\ =0.6\text{m}/{\text{s}}^2\end{array}$

Therefore, the acceleration of the objects that are glued together is $0.6\text{m}/{\text{s}}^2$.