According to the kinetic energy theorem, the motion process of (1)P in horizontal orbit is obtained;

-μm 1gx = 0- 12m 1v 2 1

Therefore, the speed of P passing through point A is v1= 2μ gs = 2× 0.25x10x1.25m/s = 2.5m/s.

(2) In the process of P from B to A, the rising height of Q is H = H2+L2 =1m..

Then the increment of q gravitational potential energy in the process of p from b to a △EP=mgH=4J.

(3) Let the speed of Q be v2 when P passes through point A, and the speed of decomposing P is v 1, as shown in the figure.

There is v2=v 1cosα.

Sinα=hH=0.6，α = 37。

For the system composed of p and q, according to the kinetic energy theorem:

m 1gh-m2gH+Wf = 12m 1v 2 1+ 12m 2v 22

Substituting the data, it is found that the work done by the curve track on the friction of P is WF =-0.95 J. 。

A:

(1) The speed of P passing through point A is 2.5m/s;

(2) In the process of P from B to A, the increment of Q gravitational potential energy is 4J;

(3) The work done by the curved track to the friction P is-0.95 J. 。