Clarice

Two charged dust particles exert a force of 3.0×10−2 N on each other. What will be the force if they are moved so they are only one-eighth as far apart?

What is the magnitude of the force a +30 μC charge exerts on a +2.5 mC charge 45 cm away?

What is the angular momentum of a figure skater spinning at 3.2 rev/s with arms in close to her body, assuming her to be a uniform cylinder with a height of 1.6 m , a radius of 13 cm , and a mass of 48 kg? (answer for this is 8.16) How much torque is required to slow her to a stop in 4.1 s , assuming she does not move her arms?

What is the angular momentum of a 0.335 kg ball rotating on the end of a thin string in a circle of radius 1.45 m at an angular speed of 10.8 rad/s ?

A merry-go-round with a moment of inertia equal to 1300 kg⋅m2 and a radius of 2.5 m rotates with negligible friction at 1.70 rad/s. A child initially standing still next to the merry-go-round jumps onto the edge of the platform straight toward the axis of rotation, causing the platform to slow to 1.35 rad/s.What is her mass?

Hello! Can I please have some help with these questions?

The forearm in the figure (is attached) accelerates a 2.8 kg ball at 5.1 m/s2 by means of the triceps muscle, as shown. Calculate the torque needed. Ignore the mass of the arm. Calculate the force that must be exerted by the triceps muscle.

Determine the moment of inertia of a 11.6 kg sphere of radius 0.647 m when the axis of rotation is through its center.

Block 1, of mass m1 = 1.50 kg , moves along a frictionless air track with speed v1 = 27.0 m/s . It collides with block 2, of mass m2 = 31.0 kg , which was initially at rest. The blocks stick together after the collision. Find the magnitude pi of the total initial momentum of the two-block system.Find vf, the magnitude of the final velocity of the two-block system. What is the change ΔK=Kfinal−Kinitial in the two-block system's kinetic energy due to the collision? - not gonna lie, I don't know where to go at all

A 129-kg astronaut (including space suit) acquires a speed of 2.40 m/s by pushing off with her legs from a 1850-kg space capsule. Use the reference frame in which the capsule is at rest before the push. What is the velocity of the space capsule after the push in the reference frame? If the push lasts 0.680 s , what is the magnitude of the average force exerted by each on the other? What is the kinetic energy of the astronaut after the push in the reference frame? What is the kinetic energy of the capsule after the push in the reference frame? - I have no idea how to do this one either :(

A 85-kg fullback is running at 3.1 m/s to the east and is stopped in 0.85 s by a head-on tackle by a tackler running due west. Calculate the original momentum and impulse exerted of the fullback. Calculate the average force and exertion exerted on the tackler - I got 300 kg m/s for the momentum of the fullback.

A 0.060-kg tennis ball, moving with a speed of 5.66 m/s , has a head-on collision with a 0.085-kg ball initially moving in the same direction at a speed of 3.60 m/s . Assume that the collision is perfectly elastic. Determine the speed of the 0.060-kg ball after the collision. - I understand that the speed is in the direction of the initial velocity but I am so lost beyond that

A 990-kg sports car collides into the rear end of a 2100-kg SUV stopped at a red light. The bumpers lock, the brakes are locked, and the two cars skid forward 2.7 m before stopping. The police officer, estimating the coefficient of kinetic friction between tires and road to be 0.80, calculates the speed of the sports car at impact. What was the speed sports car at impact? - I got 81761 for the KE but I'm not sure where to go from there.

A child in a boat throws a 5.80-kg package out horizontally with a speed of 10.0 m/s. The mass of the child is 22.8 kg and the mass of the boat is 36.6 kg. Calculate the velocity of the boat immediately after, assuming it was initially at rest. - I got -0.914 m/s but it says it's not right

A 0.265-kg ball makes an elastic head-on collision with a second ball initially at rest. The second ball moves off with half the original speed of the first ball. What is the mass of the second ball? - I got 0.84 kg, also not right.

A 144-g baseball moving 26 m/s strikes a stationary 5.25-kg brick resting on small rollers so it moves without significant friction. After hitting the brick, the baseball bounces straight back, and the brick moves forward at 1.25 m/s. Determine the baseball's speed after the collision, Determine the total kinetic energy before the collision, Determine the total kinetic energy after the collision. - I got 13.7 m/s for the speed but since that is wrong, I figured that doing the rest would be wrong.

An internal explosion breaks an object, initially at rest, into two pieces: A and B. Piece A has 2.3 times the mass of piece B. The energy of 6000 J is released in the explosion. Determine the kinetic area of piece A and B. - For point A, I got 2700 J but I'm not sure how to get from there to point B.

I tried to do a lot of the problems but I kept getting the answers wrong! Please help :)

At what rate must a cylindrical spaceship rotate if occupants are to experience simulated gravity of 0.64 g? Assume the spaceship's diameter is 40 m , and give your answer as the time needed for one revolution

A block of mass m is attached to the end of a spring (spring stiffness constant k), The mass is given an initial displacement x0 from equilibrium, and an initial speed v0.

Ignoring friction and the mass of the spring, use energy methods to find its maximum speed in terms of the given quantities.

Find its maximum stretch from equilibrium in terms of the given quantities.

Express your answer in terms of the variables m, v0, x0, and k.

1) A 29 kg boy climbs a 15 m rope in 45 s. What was his average power output? Use g = 10 m/s2.

2) What is the minimum work needed to push a 850 -kg car 760 m up along a 9.0 ∘ incline? Ignore friction.

3) At an accident scene on a level road, investigators measure a car's skid mark to be 91 m long. It was a rainy day and the coefficient of friction was estimated to be 0.35. Use these data to determine the speed of the car when the driver slammed on (and locked) the brakes.

How fast is she going when she reaches the bottom?

What is the maximum speed with which a 1200-kg car can round a turn of radius 81.0 m on a flat road if the coefficient of static friction between tires and road is 0.60?

How large must the coefficient of static friction be between the tires and the road if a car is to round a level curve of radius 135 m at a speed of 115 km/h ?

What is the magnitude of the acceleration of a speck of clay on the edge of a potter's wheel turning at 47 rpm (revolutions per minute) if the wheel's diameter is 39 cm ?

A horizontal force of 340 N is exerted on a 2.5-kg ball as it rotates (at arm's length) uniformly in a horizontal circle of radius 0.90 m.Calculate the speed of the ball.

A child sitting 1.60 m from the center of a merry-go-round moves with a speed of 1.65 m/s . Calculate the centripetal acceleration of the child.

Calculate the net horizontal force exerted on the child. (mass = 24.5 kg )