Question

1. a 12 kg object moving at 4 m/s comes to a complete stop. what is the magnitude of the impulse required to stop the object? j = δp or j = p_f - p_i the magnitude of the impulse required to stop the object is ____ kg(m)/s define: electromagnetic force: __________ gravitational force: ____________ 19)which of the following statements about gravitational and electromagnetic forces is correct? a. gravitational force can only be attractive between two massive objects. b. electromagnetic force depends only on the distance between two charged particles, not their charge. c. gravitational force is always the result of charged particles. d. electromagnetic force is always attractive between two like charges. 20) which of the following is the best explanation for why the moon has less gravity than earth? a. the moon has a thinner atmosphere than earth. b. the moon is farther from the sun than earth. c. the moon has less mass than earth. d. the moon has a weaker magnetic field than earth.

Explanation:

Step1: Recall impulse - momentum theorem

Impulse $J=\Delta P = P_f - P_i$. The final momentum $P_f$ of the object is 0 since it comes to a stop. The initial momentum $P_i=mv$, where $m = 12$ kg and $v = 4$ m/s.

Step2: Calculate initial momentum

$P_i=mv=12\times4 = 48$ kg(m)/s.

Step3: Calculate impulse

$J=\Delta P=P_f - P_i=0 - 48=- 48$ kg(m)/s. The magnitude of the impulse is 48 kg(m)/s.

Electromagnetic force is the force between charged particles, which can be attractive or repulsive depending on the charges. Gravitational force is the force of attraction between two masses, proportional to the product of their masses and inversely proportional to the square of the distance between them.

Option A is correct because gravitational force is always attractive between two massive objects. Option B is wrong as electromagnetic force depends on both the distance between charged particles and their charges. Option C is wrong since gravitational force is not related to charged particles but to masses. Option D is wrong because electromagnetic force is repulsive between two like - charges.

Gravitational force is proportional to the mass of an object. Since the moon has less mass than Earth, it has less gravitational force. The atmosphere, distance from the Sun, and magnetic field do not directly determine the gravitational force of a celestial body.

Answer:

48