1- The real length of a pen is 10 cm. A student measured it as 9.9 cm. Find absolute and relative error? ∆X X0 ! X 10-9.9 0.1 r = ∆ X X 0 = 0.1 10 = 0.01 = 1 "ength of pen #10 $ 0.1% cm &- The real length of class is 9.11 m. A student measured it as 9.1' m. find absolute and relative error? ∆X X0 ! X 9.11 ! 9.1' 0.0& r = ∆ X X 0 = 0.02 9.11 = 0.0022 "ength of class #9.11 $ 0.00&&% m '- Find absolute and relative error (hen measuring area A of a rectangle its length is #) $ 0.1% m and its (idth is #* $ 0.&% m. Area A length + (idth ,elation used is multipl +o * + ) '0 m & r1 0.1 ) 0.01/ r& 0.& * 0.0 r total r1 r&0.01/ 0.0 0.0*/ r = ∆ X X 0 so,∆ X = r . X 0 ¿ 30 x 0.057 1./ - 2f " " 1 " & find " (here3 " 1 #*.& ± 0.1¿ 4 " &*.5 ± 0.2 *- An athlete has moved to 6est through a displacement of #*0 m %4 then moved bac7 to 8ast through a displacement of #'0 m %. alculate the distance covered and the displacement of the athlete. First: the covered distance3 3 s = 50 + 30= 80 m Second: the displacement of the athelet3 d = +50 - 30 = +20 m )- Find the resultant of t(o forces: one of them #F + ; % acting in + dimension4 (hile the other F '; acting in dimension. /-2f the magnitudes of t(o vectors Are A * and <10 respectivel and the angle bet(een them is )0=4 find the result of each of dot product and cross product 5- A person drove a car in a straight line to cover 8.4 7m in0.12 h . <ecause the fuel had run out4 he (al7ed through 2 km along the same straight line to reach the nearest gas station after 0.5 h . alculate the average velocit of this >ourne 9- 2f the person in the previous e+ample returned bac7 to his car in 0.6 h find the average velocit and speed during the (hole >ourne V aV = displacement time ¿ 8.4 0.12 + 0.5+ 0.6 = 6.88 km / hr V aV = distance time ¿ 8.4+ 2 + 2 0.12 + 0.5+ 0.6 =¿ 11- An aeroplane lands on the run(a at velocit 1)& 7m h and decelerates uniforml at 0.* m s & Find the time it ta7es till stops. 1&- ohamed drove a car at uniform velocit #'0 m s%. @uddenl 4 he sa( a childcrossing the street and he applied the bra7es to decelerate the car uniforml at #9 m s%. 2f ohamed s reaction time to use the bra7es is #0.*s%4 find the Bisplacement of the car till it stopped. The moon rotates arround the earth in a circular orbit (hose radius is '.5*+ 10 * 7m.2t ma7es a complete revolution through #&/.' da s%. alculate the mass of the earth Cniversal gravitation constant 6.67 × 10 -11 @olution3 Deriodic time3 T = 27.3 × 24 × 60 × 60 = 2.36 × 10 6 s 1'-A bo+ fell from a helicopter t (as sta ing still at /5. m high above sea level. Find the velocit b (hich the bo+ hit (ater giving t ha t acceleration due to gravit 9.5 m s neglecting the air resistance. Al Find the time it too7 till splash 1 - A stone fell from the roof of building. 2f the stone passed b a person standing in a balcon *m h above the ground s later #consi 10 m s%4 find3 A- The building height. <- The stone velocit (hen passed the person. A cart of mass &0 7g is pulled b a force of *0; .The line of action of the force ma7es an angle )0 0 to the