scientists are experimenting with a king of gun that may eventually be used to fire  payloads directly into orbit. in one test, this gun accelerates a 3.8 kg projectile from rest to a speed of 5.2 * 10^3 m/s. the net force accelarating the projectile is 2.5 * 10^5 N. how much time is required for the projectile to come up to speed?

If I shot an arrow straight up into the air, it would leave my bow traveling at a rate of 140 feet per second. Assume that the arrow is so "slick", that there is no friction (or air resistance). Without gravity it would continue to travel at this speed. After 8 seconds it would have traveled 8*140 feet. But, gravity will pull it back to the earth. The gravitational pull is measured as 16t2. So the height at any time t can be measured by the function h(t) = 140t - 16t2. At what time t will the arrow reach it's maximum height?

A 4.2-g bullet leaves the muzzle of a rifle with a speed of 326 m/s. What force (assumed constant) is exerted on the bullet while it is traveling down the 0.78-m-long barrel of the rifle? ____ N

A hockey puck with mass 0.1 kg is at rest at the origin (x = 0) on the horizontal, frictionless surface of the rink. At time t = 0 a player applies a force of 0.2 N to the puck, parallel to the x-axis; she continues to apply this force until t = 2 5. (a) What is the speed of the puck at t = 2 s? Round your answer to 2 decimal places.

How fast will the fish be moving after swimming 1 m?

Consider a tennis ball of mass 0.040 kg making contact with a racquet at 23.7 m/s for 1.30 ms. If the return speed (assume 1-D motion) is 22.4 m/s, calculate the magnitude of the average force on the ball by the racquet. 0.900 x 10³ N O 1.260 x 10³ N 1.245 x 10³ N O 2.170 x 10³ N O 1.420 x 10³ N

Your forehead can withstand a force of about 6.0 kN before fracturing, while your cheekbone can withstand only about 1.3 kN. Suppose a 140 g baseball traveling at 27 m/s strikes your head and stops in 1.1 ms What force does the baseball exert on your head? What is the magnitude of the force that stops the baseball?

Kyle, a 95.0 kg football player, leaps straight up into the air (with no horizontal velocity) to catch a pass. He catches the 0.430 kg ball precisely at the peak of his jump, when he is 0.538 meters off the ground. He hits the ground 0.0333 metersaway from where he leapt. If the ball was moving horizontally when it was caught, how fast was the ball traveling?   ball's speed: ? m/s

30. An object of mass m, V 4.00 kg is tied to an object of mass m, 3.00 kg with String 1 of length l = 0.500 m. The combination is swung in a vertical circular String 1 e m2 String 2 path on a second string, String 2, of length € = 0.500 m. During the motion, the two strings are collinear at all times as shown in Figure P6.30. At the top of its motion, m, is traveling at v = 4.00 m/s. (a) What is the tension in String 1 at this instant? (b) What is the tension in String 2 at this instant? (c) Which string will break first if the combina- Figure P6.30 tion is rotated faster and faster?

An outfielder throws a 0.148 kg baseball with velocity 30 m/s at 25° above horizontal. Ignoring air resistance: what gravity PE did the ball have, relative to the player's level, at its peak?