Kinematics PYQs Set 6 (PDF)

Set 6 of 12 · Questions 151-180 of 359

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Mere Teacher · Previous Year Questions NEET Physics · Kinematics · Set 6 (Q151-180)
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151. $Which of the following decreases, in motion on a straight line, with constant retardation?$ (1) $Speed$ (2) $Acceleration$ (3) $Displacement$ (4) $Distance$ 152. $The resultant magnitude of two vectors of same magnitude is equal to magnitude of either. The angle between the two vectors is$ (1) $30^{\circ}$ (2) $60^{\circ}$ (3) $90^{\circ}$ (4) $120^{\circ}$ 153. $The maximum vertical height to which a man can throw a ball is 136 m. The maximum horizontal distance upto which he can throw the same ball is$ (1) $192m$ (2) $136m$ (3) $272 m$ (4) $68 m$ 154. $Which of the following statements is true regarding the vector product of two vectors?$ (1) $The vector product of two vectors changes sign under reflection$ (2) $Vector product is commutative.$ (3) $Vector product of two parallel vectors is a null vector.$ (4) $Vector product of two vectors is a scalar.$ 155. $A body is moving with velocity 30 m/s towards east. After 10 seconds its velocity becomes 40 m/s towards north. The average acceleration of the body is:$ (1) $1 m/ s^{2}$ (2) $7 m/ s^{2}$ (3) $m/ s^{2}$ (4) $5 m/ s^{2}$ 156. $The component of a vector r along x -axis will have a maximum value if$ (1) $r is along +ve x -axis$ (2) $r is along +ve y -axis$ (3) $r is along-ve y -axis$ (4) $r makes an angle of 45^{\circ} with the x-axis$ 157. $An object of mass 5 kg is thrown vertically upwards from the ground. The air resistance produces a constant retarding force of 10 N throughout the motion. The ratio of time of ascent to the time of descent will be equal to : [Use g = 10 m s^{- 2}]$ (1) $1 : 1$ (2) $2 : 3$ (3) $3 : 2$ (4) $2 : 3$ 158. $A particle moves from the point (2.0 i^+ 4.0 j^) m, at t = 0, with an initial velocity (5.0 i^+ 4.0 j^) m s^{- 1} . It is acted upon by a constant force which produces a constant force which produces a constant acceleration (4.0 i^+ 4.0 j^) m s^{- 2} . What is the distance of the particle from the origin at time 2 s?$ (1) $202 m$ (2) $15 m$ (3) $102 m$ (4) $5 m$ 159. $At a metro station, a girl walks up a stationary escalator in 20 sec . If she remains stationary on the escalator, then the escalator take her up in 30 sec . The time taken by her to walk up on the moving escalator will be$ (1) $12 sec$ (2) $10 sec$ (3) $25 sec$ (4) $60 sec$ 160. $A projectile is projected with velocity of 25 m/s at an angle θ with the horizontal. After t seconds its inclination with horizontal becomes zero. If R represents horizontal range of the projectile, the value of θ will be : [use g = 10 m/ s^{2}]$ (1) $\frac{1}{2} sin^{- 1} (\frac{5 t ^{2}}{4 R})$ (2) $\frac{1}{2} sin^{- 1} (\frac{4 R}{5 t ^{2}})$ (3) $tan^{- 1} (\frac{4 t ^{2}}{5 R})$ (4) $cot^{- 1} (\frac{R}{20 t ^{2}})$ 161. $A car starts at time t = 0 from an initial speed of 10 m / s and accelerates uniformly with 2 m / s^{2} on a straight road for time 0 \leq t \leq 10 s . Let S_{1} and S_{2} be the distance covered by the car in time 3 \leq t \leq 4 s and 4 \leq t \leq 5 s respectively. The ratio \frac{S _{2}}{S _{1}} is$ (1) $1$ (2) $\frac{19}{7}$ (3) $\frac{9}{7}$ (4) $None$ 162. $The trajectory a projectile in a vertical plane is y = αx - β x^{2}, where α and β are constants and x ∖ & y arerespectively the horizontal and vertical distance of the projectile from the point of projection. The angle ofprojection θ and the maximum height attained H are respectively given by:$ (1) $tan^{- 1} α, \frac{α ^{2}}{4 β}$ (2) $tan^{- 1} β, \frac{α ^{2}}{2 β}$ (3) $tan^{- 1} (\frac{β}{α}), \frac{α ^{2}}{β}$ (4) $tan^{- 1} α, \frac{4 α ^{2}}{β}$ 163. $A person standing on the floor of an elevator drops a coin. The coin reaches the floor in time t_{1} if the elevator is moving uniformly. Then depending upon whether the lift is going up or down$ (1) $t_{1} < t_{2} or t_{1} > t_{2}$ (2) $t_{1} < t_{2}$ (3) $t_{1} > t_{2}$ (4) $t_{1} = t_{2}$ 164. $A projectile with speed 50 ms^{- 1} is thrown at an angie or 60^{\circ} with the horizontal. The maximum height that can be reached is$ (1) $90.75 m$ (2) $70.00 m$ (3) $. 85.00 m$ (4) $93.75 m$ 165. $particle is moving unidirectionally on a horizontal plane under the action of a constant power upplying energy source. The displacement (s) - time (t) graph that describes the motion of the particle (graphs are drawn schematically and are not to scale)$ (1) (2) (3) (4) 166. $A particle moving along X -axis has acceleration f at time t given by f = f_{0} (1 - \frac{t}{T}), where f_{0} and T are constants The particle at t = 0 has zero velocity. In the time interval between t = 0 and the instant when f = 0, the particle's velocity is$ (1) $\frac{1}{2} f_{0} T^{2}$ (2) $f_{0} T^{2}$ (3) $\frac{1}{2} f_{0} T$ (4) $f_{0} T$ 167. $The time of flight of a vertically projected stone is 8 s . The position of the stone after 6 s from the ground is (Acceleration due to gravity = 10 ms^{- 2})$ (1) $20 m$ (2) $60 m$ (3) $75 m$ (4) $40 m$ 168. $A body is projected from the ground at an angle of tan^{- 1} (\frac{8}{7}) with the horizontal. The ratio of the maximum height attained by it to its range is$ (1) $8 : 7$ (2) $4 : 7$ (3) $2 : 7$ (4) $1 : 7$ 169. $The velocity of an object moving in a straight line path is given as a function of time by v = 6 t - 3 t^{2}, where v is in ms^{- 1}, t is in s . The average velocity of the object between, t = 0 and t = 2 s is$ (1) $0$ (2) $3 ms^{- 1}$ (3) $2 ms^{- 1}$ (4) $4 ms^{- 1}$ 170. $Water drops fall from a tap on the floor, 5 m below, at regular intervals of time, the first drop strikes the floor when the sixth drop begins to fall. The height at which the fourth drop will be from ground, at the instant when the first drop strikes the ground is____m. (g = 10 m / s^{2})$ (1) $4.2$ (2) $2.5$ (3) $4.0$ (4) $3.8$ 171. $The maximum range of a gun on horizontal plane is 16 km . If g = 10 m s^{- 2}, then muzzle velocity of a shell is$ (1) $160 m s^{- 1}$ (2) $2002 m s^{- 1}$ (3) $400 m s^{- 1}$ (4) $800 m s^{- 1}$ 172. $Look at the graphs (a) to (d) carefully and indicate which of these possibly represents one dimensional motion of a particle?$ (1) (2) (3) (4) 173. $A river 200 m wide is flowing at a rate of 3.0 m / s . A boat is sailing at a velocity of 15 m / s with respect to the water in a direction perpendicular to the river. How far from the point directly opposite to the starting point does the boat reach on the opposite bank?$ (1) $25 m$ (2) $60 m$ (3) $40 m$ (4) $50 m$ 174. $A projectile is launched at an angle ' α' with the horizontal with a velocity 20 m s^{- 1} . After 10 s, its inclination with horizontal is ' β'. The value of tan β will be : (g= 10 m s^{- 2})$ (1) $tan α + 5 sec α$ (2) $tan α - 5 sec α$ (3) $2 tan α - 5 sec α$ (4) $2 tan α + 5 sec α$ 175. $A ball of mass 100 g is projected with velocity 20 m / s at 60^{\circ} with horizontal. The decrease in kinetic energy of the ball during the motion from point of projection to highest point is$ (1) $5 J$ (2) $15 J$ (3) $20 J$ (4) $zero$ 176. $player kicks a football with an initial speed 25 m s^{- 1} of at an angle of 4 5^{0} from the ground. What are the maximum height and the time taken by the football to reach at the highest point during motion ? (Take g = 10 m s^{- 2})$ (1) $hmax = 10 m T = 2.5 s$ (2) $hmax = 15.625 m T = 3.54 s$ (3) $hmax = 15.625 m T = 1.77 s$ (4) $hmax = 3.54 m T = 0.125 s$ 177. $A helicopter flying horizontally with a speed of 360 km / h at an altitude of 2 km, drops an object at an instant. The object hits the ground at a point O, 20 s after it is dropped. Displacement of ' O' from the position of helicopter where the object was released is: (use acceleration due to gravity g = 10 m / s^{2} and neglect air resistance)$ (1) $7.2 km$ (2) $25 km$ (3) $22 km$ (4) $4 km$ 178. $From a tower of height H, a particle is thrown vertically upwards with a speed u. The time taken by the particle, to hit the ground, is a n times that taken by it to reach the highest point of its path. The relation between H, u and n is:$ (1) $2 g H = n^{2} u^{2}$ (2) $g H = (n - 2)^{2} u^{2}$ (3) $2 g H = n u^{2} (n - 2)$ (4) $g H = (n - 2) u^{2}$ 179. $An archer shoots an arrow from a height 4.2 m above the ground with a speed 40 m / s and at an angle 30^{\circ} as shown in the figure. Determine the horizontal distance R covered by the arrow, when it hits the ground, (Take g = 10 m / s^{2})$ (1) $\frac{185}{3} m$ (2) $843 m$ (3) $683 m$ (4) $\frac{95}{3} m$ 180. $A particle is moving with constant speed in a circular path. When the particle turns by an angle 90°, the ratio of instantaneous velocity to its average velocity is π : x 2 . The value of x will be$ (1) $2$ (2) $5$ (3) $1$ (4) $7$