Recent content by physicsquest

I don't understand how to solve the 2nd part without given the coefficient of friction.

Homework Statement A 25.0kg child on a 2.00m long swing is released from rest when the ropes of the swing make an angle of 30 degrees with the vertical. (a) Neglecting friction, find the child's speed at the lowest position. (b) If the actual speed of the child at the lowest position is 2.00...

Homework Statement A 5.0g bullet leaves the muzzle of a rifle with a speed of 320 m/s. What force (assumed constant) is exerted on the bullet while it is traveling down the 0.82 m long barrel of the rifle? Homework Equations \SigmaF=ma The Attempt at a Solution

Homework Statement A hiker has managed to strand himself in the wilderness. A rescue plane traveling at 80.0 km/h horizontally and at an altitude of 70.0 m airdrops some survival supplies for his use. If the goods are thrown down at 2.50 m/s in the vertical direction with respect to the...

Between the 0 month and 6 month positions would I take (1.50 X 10^11) + (1.50 X 10^11)?

So do I just take the square root of ((1.50 X 10^11)^2 + (1.50 X 10^11)^2) to get the magnitude of the displacement vector?

Homework Statement At the entrance of Ambrose Channel at New York harbor, the tidal current at one time of the day has a velocity of 4.2 km/h in a direction 20 degrees south of east. Consider a ship in this current; suppose that the ship has a speed of 16 km/h relative to the water. If the...

Homework Statement In a flying ski jump, the skier acquires a speed of 110 km/h by racing down a steep hill and then lifts off into the air from a horizontal ramp. Beyond this ramp, the ground slopes downward at an angle of 45 degrees. (a) Assuming the skier is in a free-fall motion after he...

Homework Statement The Earth moves around the Sun in a circle of radius 1.50 X 10^11 m at approximately constant speed. Taking today's position of the Earth as origin, draw a diagram showing the position vector 3 months, 6 months, 9 months, and 12 months later. Draw the displacement vector...

I'm still not sure what vf and vi are though. I tried dividing height by time and I used t= (-2(x-xo)/g)^1/2 to find times, but I'm still not getting the right answer.

Homework Statement A golf ball released from a height of 1.5m above a concrete floor bounces back to a height of 1.1m. If the ball is in contact with the floor for 6.2 X 10^-4 s, what is the average acceleration of the ball while in contact with the floor? g= 9.81 m/s^2 x-xo= -1.5 vo= 0...

How do you calculate initial velocity without time given?

Homework Statement In a collision, an automobile initially traveling at 50 km/h decelerates at a constant rate of 200 m/s^2. A passenger not wearing a seat belt crashes against the dashboard. Before the collision, the distance between the passenger and the dashboard was 0.60 m. With what...

Homework Statement In a collision, an automobile initially traveling at 50 km/h decelerates at a constant rate of 200 m/s^2. A passenger not wearing a seat belt crashes against the dashboard. Before the collision, the distance between the passenger and the dashboard was 0.60 m. With what...