Mechanics | Relativity Answers

A watermelon cannon fires a watermelon vertically up into the air at a velocity of +9.00 m/s, starting from an initial position 1.20 meters above the ground. When the watermelon reaches the peak of its flight, what is (a) its velocity, (b) its acceleration, (c) the elapsed time, and (d) its height above the ground?

Three force F1 , F2, F3 act on a 5.00 kg object . The angle between F1 and F2 is 60 degree the angle between F2 and F3 is 30 degree .Taking F1 = 20.0 N and F2 = 15.0 and F3 = 10.0 N
A )- Find the magnitude and direction of the net force acting on the object ?
B)- Find the magnitude and direction of the acceleration of the object ?

A spring is compressed between two carts and is temporarily clamped so that the carts and spring move as a single unit. Initially, the carts move towards the right on a level surface with a velocity of 2.80 m/s. The masses of the the carts are 1.60 kg and 2.50 kg, on the left and right respectively. The mass of the spring is much smaller than that of either carts and can be neglected. At an certain instant, the clamp is suddenly released, and the carts separate, with cart, on the right, move to the right at 3.20 m/s.
1. Calculate the velocity of the cart, on the left, immediately after the decompression of the spring.
2. As a result of this interaction, do you expect the final total kinetic energy of the system to be equal to, greater than or less than the total initial kinetic energy?Explain your reasoning and support you reasons with relevant calculations.
3.Does this event described, invovles elastic collision? Explain your answer.

The gravitational force between two sumo wrestlers just before they collide (r=0.0250m) is 2.770*10^-3 N.
If one wrestler has a mass of 157.0 kg, what is his opponents mass?

Find the force of gravity between you(70.0kg) and a pencil (1.20g) at a distance of 0.500m

A balloon is travelling vertically upward with velocity 20 (m/s) after it is on height 100m above the ground , an object was thrown down with velocity 10(m/s) towards the ground but it falls in another balloon which is 80m above the ground and stationery without wasting a second the person in 2nd balloon drops that fallen object down from the balloon but unfortunately it agains fall in a stationary balloon which is 50m above the ground as soon as the object falls in that balloon ,without wasting a second, balloon starts accelrating upwards with accelration 20(m/s^2) after travelling for 3 seconds the object was dropped down from the balloon and falls on ground. (a) find the total time taken by the object to fall on the ground from the starting .(b)find the final velocity when it falls on the ground.

A spherical body of mass m and radius r is allowed to fall in a medium of viscosity n.The time in which the velocity of the body increases from zero to 0.65 times the terminal velocity v is called the time constant t.The dimensions of t are (i)m*r(r raise to power 4) by 6*pie*n (ii)6*pie*m*r*n by g(g raise to power 2) whole under the root (iii)m by 6*pie*n*r*v (iv)none of these

What will be the unit of time in that system in which the unit of length is metre,unit of mass is 2kg and
unit of force is kg wt.? (i)9.8(raise to power 2)s (ii)9.8s (iii)1 by 4.9(raise to power half)s (iv)4.9s

A 190 kg block is released at a 5.2 m height
as shown. The track is frictionless except for
a portion of length 6.6 m. The block travels
down the track, hits a spring of force constant
1980 N/m. The coefficient of kinetic friction
between surface and block over the 6.6 m
track length is 0.58 .
Determine the compression of the spring x
from its equilibrium position before coming to
rest momentarily. The acceleration of gravity
is 9.8 m/s2 .
Answer in units of m.

A car starts from rest and accelerates uniformly for 10 s to a velocity of 8 m/s . It runs at a constant velocity and is finally brought at rest in 64 m with a constant retardation . the total distance covered by the car is 584 m . find the value of acceleration, retardation and total time taken.