Throwing and Catching at Same Height

Q. Read each statement below carefully and state with reasons and examples, if it is true or false ; A particle in one-dimensional motion (a) with zero speed at an instant may have non-zero acceleration at that instant (b) with zero speed may have non-zero velocity, (c) with constant speed must have zero acceleration, (d) with positive value of acceleration must be speeding up.

Q. 14. The acceleration of moon with respect to earth is 0.0027ms-2 and acceleration of an apple falling on earth surface is about 10ms-2. Assume that the radius of the moon is one fourth of the earth radius. If the moon is stopped for an instant and then released , it will fall towards the earth . Calculate 1. The initial acceleration of the moon towards the earth will be. 2. The acceleration of the moon just before it strikes the earth

Q.

A particle is projected with velocity 50 m/sec at angle 37° with horizontal, then change in velocity of particle from point of projection to just before striking ground is :-

(1)	zero
(2)	60 m/sec
(3)	80 m/sec
(4)	100 m/sec

Q. escape velocity of 1 kg body on a planet is 100m/s .potential energy at that planet i

Q.

What is the acceleration of the ball at the highest point?

1. 9.8 m/s²

2. -9.8 m/s²

3. none of these

4. 0 m/s²

Q. A ball of mass m is thrown from ground with speed u at an angle θ with horizontal.Find the power when the ball is at maximum height of the trajector

Q. 25 a ball is projected with 20 root(2) m/s at an angle 45 degrees with horizontal.the angular velocity of particle at highest point of its journey about projection is

Q. 30. A gun mounted on the top of a moving truck is aimed in the backward direction at an angle of 30�to the vertical . If the muzzle velocity of the bullet fired from the gun is 4 m/s , then the speed of the truck that will make the bullet come out vertically is - a) 0.5 m/s b) 1m/s c) 1.5 m/s d) 2m/s

Q. a stone is thrown upwards and it rises to a height of 200m .the relative velocity of the stone with respect to earth will be maximum at 1. height of 100m 2.height of 150m 3. highest point 4.the ground

Q. 52 A body thrown vertically up from the ground passes theheight of 10.2 m twice in an interval of 10 s. What was itsinitial velocity?(a) 52 ms(b) 61ms(c) 45 ms(d) 26 ms

Q. A car take turn in a circle of radius 50 m. If velocity of car is 25 m/s, then the angle made by massless rod of pendulum suspended from the ceiling of car with vertical is (mass of perpendicular bob is 50 g) 1. tan-1 (5/4) 2. tan-1 (4/5) 3. tan-1(4) 4. tan-1(1/4)

Q. a boy s†an ds 39.2m from a building and throws a ball which just passes through a window 19.6m above the ground velocity of projection of ball is

Q.

A boy stands at the bottom of a 39.2 m tall building. He throws a ball upward which just reaches a window 19.6 m above the ground. What is the velocity of projection?

Q. 64 equal drops of water are falling through air with a terminal velocity of 10m\backslash sec .if these drops coalesce , what will be the velocity of the big drop form

Q. 51.A stone is thrown vertically upwards with an initial velocity of v. What is the distance travelled by it in time 1.5v /g ?

Q. A very small groove is made in the earth, anda particle of mass mo is placed at R/2 distance from the centreas shown is figure. Find the escape energy of the particle fromthat place.

Q.

A ball is thrown up from the top of a tower with 20 m/s velocity. It took the ball 6 sec to fall to the bottom. How much distance did the ball cover in the last second of its motion?

1. 25 cm

2. 15 cm

3. 60 cm

4. 35 cm

Q.

A boy standing on a stationary lift (open from above) throws a ball upwards with the maximum initial speed $=49m/s$.
a) How much time does the ball take to return to his hands?
b) If the lift starts moving up with a uniform speed of $5m/s$ and he again throws the ball , how long does it take to return to his hands ?

Q. A raindrop falling from a height h above the4ground attains the terminal velocity when it hasfallen through a height h The diagrams shown5in figure, which correctly shows the change inpotential and kinetic energy of the drop during itsfall up to ground isPEPE(1)(2)KEKEPE(4) h(3)PEh5 TKEKE(1)clo14

Q. A stone of mass m is thrown at an angle of 60^° above the horizontal axis from the ground. Thekinetic energy of the stone at the highest point(If K is the kinetic energy of the stone at the timeof projection) will be

Q.

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 $n$ times that taken by it to reach the highest points of its path. What is the relation between $H$, $u$, and $n$?

Q. PHYSICS- GRAVITATION A hydrogen balloon released on the moon A)Climbs up with an acceleration 6x9.8ms_-2 B)Climbs up with an acceleration of 9.8/6ms_-2 C)Bursts D)Falls with an acceleration of 9.8/6 ms_-2

Q. A player throws a ball upwards with an initial speed of $29.4m{s}^{-1}$.
(a) What is the direction of acceleration during the upward motion of the ball ?
(b) What are the velocity and acceleration of the ball at the highest point of its motion ?
(c) Choose x = 0 m and t = 0 s to be the location and time of the ball at its highest point, vertically downward direction to be the positive direction of x-axis, and give the signs of position, velocity and acceleration of the ball during its upward, and downward motion.
(d) To what height does the ball rise and after how long does the ball return to the players hands ? (Take $g=9.8m/s^2$ and neglect air resistance).

Q. A stone is thrown vertically upward with an initial velocity $v_o.$ The distance travelled in time $\frac{1.5v_o}{g}$ is

1. $\frac{v_o^2}{2g}$
2. $\frac{3v_o^2}{8g}$
3. $\frac{5v_o^2}{8g}$
4. None of these

Q. 30.A boy stands at 39.2m from a building and throw a ball which just passes through a window 19.6 m above the ground , find velocity of projection

Q. 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 $n$ times the time taken by it to reach the highest point of its path. The relation between $H$, $u$ and $n$ is

1. $2gH=n^2{u}^2$
2. $gH=(n-2{)}^2{u}^2$
3. $2gH=n{u}^2(n-2)$
4. $2gH=(n-2{)}^2{u}^2$

Q. A stone is thrown vertically upward with an initial velocity $v_o$. The distance travelled in time $\frac{4v_o}{3g}$ is

1. $\frac{v_o^2}{2g}$
2. $\frac{3v_o^2}{8g}$
3. $\frac{4v_o^2}{9g}$
4. $\frac{5v_o^2}{9g}$

Q. A particle of mass $5\text{kg}$ is projected on horizontal ground with an initial velocity of $10\text{m/s}$ making an angle ${30}^{\circ }$ with the horizontal. The magnitude of angular momentum of the particle about the point of projection when the particle is at the highest point is (in ${\text{kg m}}^2\text{/s}$) [Take $g=10{\text{m/s}}^2$]

1. zero
2. $250$
3. $125\sqrt{3}$
4. $\frac{125\sqrt{3}}{4}$

Q. 18. If Michael Jordan has a vertical leap of 1.29 m, then what is his takeoff speed and his hang time.

Q. A cricketer can throw a ball to a maximum horizontal distance of $100m$. How much high above the ground can the cricketer throw the same ball ?