science grade

Question: Frequency of a wave motion is 250 Hz. What is its time period? Answer: Frequency ( ) = 250 Hz ..

Question: An observer stands at a distance of 850 m from a cliff and fires a gun. After what time gap will he hear the echo, if sound travels at a speed of 350 m s - 1 in air? Answer: v = = = 4.86 ..

Question: What will be the change in kinetic energy of a body when its speed is halved? Answer: Where m is the mass of the object and v is the velocity of the object. Let T 1 be the kinetic energy of the body when its speed is halved. ..

Question: Calculate the kinetic energy of a ball of mass 10 g and momentum 1000 g cm/s. Answer: Momentum of the ball = 1000 g cm/s = 0.01 kgm/s Kinetic energy = 0.005 ..

Question: How fast should a man of mass 50 kg run, so that his kinetic energy is 625 J? Answer: ..

Question: Two bodies of equal mass move with uniform velocities v and 4 V. Find the ratio of their kinetic energies. Answer: Let m be the mass of the bodies and T 1 and T 2 represent the kinetic energy of the bodies. ..

Question: The momentum of a body of mass 60 kg is 3000 kg m/s. Calculate the kinetic energy and speed of the body. Answer: Expression for kinetic energy when momentum is given Momentum of the body = 3000 kg m/s Mass of the body = 60 kg kinetic energy = 75000 J Kinetic energy is ..

Question: A car weighing 1000 kg and travelling at 30 m/s stops at a distance of 50 m decelerating uniformly. What is the force exerted on it by the brakes? What is the work done by the brakes? Answer: Mass of the car (m) = 1000 kg Initial velocity (u) = 30 m/s Distance traveled (S)= 50..

Question: Complete the following double displacement reactions. Answer: ..

Importance of Classification - By making a comparative study and assorting the similarities and differences amongst the various varieties of species, organisms can be classified into groups or sets. Taxonomy is a regular branch of science that is involved with the purpose of arranging or ..