The metal block m is clamped in a rectangular box with compressed light spring, as shown in the figure. The upper and lower plates of the box are equipped with pressure sensors. The box can move along the vertical track, and the metal block never leaves the upper plate. When the box moves vertically with a = 2.0m/s2 acceleration, the pressure of the upper plate is 6.0N, and the pressure of the lower plate is 6.0N 0 n. (g = 10m / S2) (1) what is the gravity of the metal block? (2) If the indication of the upper roof pressure sensor is 0.4 times that of the lower floor pressure sensor, try to find the acceleration value and direction of the box. (3) to make the indication of the upper roof pressure sensor zero, what is the possible situation of the box moving along the vertical direction?

The metal block m is clamped in a rectangular box with compressed light spring, as shown in the figure. The upper and lower plates of the box are equipped with pressure sensors. The box can move along the vertical track, and the metal block never leaves the upper plate. When the box moves vertically with a = 2.0m/s2 acceleration, the pressure of the upper plate is 6.0N, and the pressure of the lower plate is 6.0N 0 n. (g = 10m / S2) (1) what is the gravity of the metal block? (2) If the indication of the upper roof pressure sensor is 0.4 times that of the lower floor pressure sensor, try to find the acceleration value and direction of the box. (3) to make the indication of the upper roof pressure sensor zero, what is the possible situation of the box moving along the vertical direction?

(1) According to Newton's second law: n lower - mg-N upper = ma, where a = - 2.0m/s2 is substituted into the data solution: M = 0.5kg, so the gravity is mg = 5N (2). If the upward direction is positive, and the lower floor pressure is n, then the upper floor pressure is 0.4N: n-0.4n-mg = ma. The solution is: a = 0.6N − MGM = 0.6 × 10 − 50.5 = 2.0m/s2