DHS 2022 JC1 MYE Physics (Solutions)

DUNMAN HIGH SCHOOL 2022 PHYSICS H2 (YEAR 5) 1 Answers to Mid-Year Exam Section A 1 2 3 4 5 6 7 8 9 10 C D C B C B D D A A 11 12 13 14 15 C A D B A 1 C 4 2 23 23 24 34 P AT kg m s mUnits of P s kg m s kg m sUnits of mK kg s K σ σ − − − −− = ×= = = = 2 D 22 1 1 () 5.0 12.0 13m s 5sin ( )13 23 Change invelocity final velocity initial velocity vvuv u Magnitudeof v θ − − = − ∆ = − = +− ∆= + = = = ° -1Thechangeinvelocityis13ms at adirection23° West of South v = 5.0 m s-1 -u = 12.0 m s-1 ∆v

DUNMAN HIGH SCHOOL 2022 PHYSICS H2 (YEAR 5) 2 3 C During fall in air, weight of ball W - viscous force F = ma The ball viscous force increases with speed, hence acceleration decreases. At terminal speed, net force is zero, hence W = F If mass m is less, terminal speed is less. At sufficiently large t, the s – t graph is a straight line as the gradient of s – t graph gives the velocity. Answer is C. 4 B ( ) 1 22 22 1 ms spe 81 ed 6 58 4 7 7 m 62 9 68 s 5 yy yx v . v u at . . . v − − = + = + = = + = −+ = 5 C Considering the free body diagram of the measuring device, 598 1 53 64 N T (. ) () T −= = 6 B The component of the weight along the slope = (12) (9.81) sin 20o = 40 N Hence resultant force = 200 – 40 = 160 N 7 D Normal reaction acts perpendicularly (normally) to the surface. W F

DUNMAN HIGH SCHOOL 2022 PHYSICS H2 (YEAR 5) 3 8 D Consider free body diagram of the mass the beaker of water T + U = M -----(1) N = W + U ------(2) From (1), U = M – T Hence, N = W + M - T 9 A 10 A ( )( )( ) 32 2 3 pressure 600 kg m 9.81 m s 20.0 10 m 1.18 10 Pa p ghρ −− − = = × = × F’ F’ a a F’’ F = ma = (2.0 + 1.0) a a = F / 3 F’ = kx1 = F / 3 x1 = F / 3k F’’ =F/3 x 2 kx2 = 2F/3 x2 = 2F / 3k = 2 x1 ⇒ x1 : x2 = 1 : 2 T M U U W N

DUNMAN HIGH SCHOOL 2022 PHYSICS H2 (YEAR 5) 4 11 C ( )( ) θ= = = o work done, cos 2.1 N 4.0 m cos30 7.3 J W Fs 12 A ( ) −= ⇒ + −= ⇒= − = = = = 1 o o constant 30 m s zero resultant force equation of motion down the slope: sin6 2000 0 2000 1500 9.81 sin6 461.9 N power output of the car's engine 13856 W 14 kW engine engine engine v F mg F Fv 13 D ( ) 50 6025 3022 5 5 2050 2 actual indicated indicated actual actual v ,v vv v v %v ωω ωω ω  = = = =   ∆= − = + ∆+ = = + 14 B ( )( ) 1 222 1 4 0.250 s4 4 4 0.250 = 4.00 s 22