Abaseball with a mass of 141 g is thrown horizontally with a speed of 40.7 m/s (91 mi/h) at a bat. the ball is in contact with the bat for 1.05 ms and then travels straight back at a speed of 45.4 m/s (102 mi/h). determine the average force exerted on the ball by the bat. neglect the weight of the ball (it is much smaller than the force of the bat) and choose the direction of the incoming ball to be positive. (indicate the direction with the sign of your answer.) n

Scientists use laser range-finding to measure the distance to the moon with great accuracy. a brief laser pulse is fired at the moon, then the time interval is measured until the "echo" is seen by a telescope. a laser beam spreads out as it travels because it diffracts through a circular exit as it leaves the laser. in order for the reflected light to be bright enough to detect, the laser spot on the moon must be no more than 1.0 km in diameter. staying within this diameter is accomplished by using a special large-diameter laser. part a if λ = 540nm , what is the minimum diameter of the circular opening from which the laser beam emerges? the earth-moon distance is 384,000 km. express your answer to two significant figures and include the appropriate units.

Avalue that describes how heavy an object is and is related to the force of gravity is

Achlorine atom has 17 protons and 18 neutrons. what is its mass number? what is its atomic number?