The goalkeeper pulls his hands backward to increase the time taken to stop the ball. This reduces the force exerted by the ball on his hands, as per impulse = change in momentum / time. Thus, the correct answer is:(b) reduce the force exerted by the ball on hands. https://www.tiwariacademy.com/ncertRead more
The goalkeeper pulls his hands backward to increase the time taken to stop the ball. This reduces the force exerted by the ball on his hands, as per impulse = change in momentum / time.
Thus, the correct answer is:(b) reduce the force exerted by the ball on hands.
(c) Isotopes of an element have different atomic masses. As the number of protons is the same, number of neutrons is different. https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-4/
(c) Isotopes of an element have different atomic masses. As the number of protons is the same, number of neutrons is different.
(b) Element with mass number 27 is Al. It has the atomic number equal to 13. Number of protons in Al atom = 13. Number of electrons in Al atom = 13. Number of electrons in Al³+ = 13 - 3 = 10. https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-4/
(b) Element with mass number 27 is Al. It has the atomic number equal to 13.
Number of protons in Al atom = 13.
Number of electrons in Al atom = 13.
Number of electrons in Al³+ = 13 – 3 = 10.
In which of the following cases of motions, the distance moved and the magnitude of displacement are equal?
(a) If the car is moving on a straight rod in a given direction. https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-7/
(a) If the car is moving on a straight rod in a given direction.
https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-7/
See lessA goalkeeper in a game of football pulls his hands backwards after holding the ball shot at the goal. This enables the goalkeeper to
The goalkeeper pulls his hands backward to increase the time taken to stop the ball. This reduces the force exerted by the ball on his hands, as per impulse = change in momentum / time. Thus, the correct answer is:(b) reduce the force exerted by the ball on hands. https://www.tiwariacademy.com/ncertRead more
The goalkeeper pulls his hands backward to increase the time taken to stop the ball. This reduces the force exerted by the ball on his hands, as per impulse = change in momentum / time.
Thus, the correct answer is:(b) reduce the force exerted by the ball on hands.
https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-8/
See lessIsotopes of an element have
(c) Isotopes of an element have different atomic masses. As the number of protons is the same, number of neutrons is different. https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-4/
(c) Isotopes of an element have different atomic masses. As the number of protons is the same, number of neutrons is different.
https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-4/
See lessIn a sample of ethyl ethanoate (CH3COOC2H5) the two oxygen atoms have the same number of electrons but different number of neutrons. Which of the following is the correct reason for it?
(c) The two oxygen atoms are isotopes. https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-4/
(c) The two oxygen atoms are isotopes.
https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-4/
See lessThe ion of an element has 3 positive charges. Mass number of the atom is 27 and the number of neutrons is 14. What is the number of electrons in the ion?
(b) Element with mass number 27 is Al. It has the atomic number equal to 13. Number of protons in Al atom = 13. Number of electrons in Al atom = 13. Number of electrons in Al³+ = 13 - 3 = 10. https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-4/
(b) Element with mass number 27 is Al. It has the atomic number equal to 13.
Number of protons in Al atom = 13.
Number of electrons in Al atom = 13.
Number of electrons in Al³+ = 13 – 3 = 10.
https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-4/
See less