Physics I- 4,5,6

An object is moving with constant speed. Which of the following best describes the force(s) acting on the object? Check all that apply. Received only 1 out of 2 points

-The net force acting on the object is zero -

On a straight road, a car is traveling West at a constant speed of 9.00m/s. After 8s, it has rounded a corner is now heading North at a constant speed of 15.0m/s. What is car's average acceleration during this 8s time interval?

0.75 m/s^2 Acceleration= change in velocity/ change in time

A 33.1-kg suitcase is being pulled along the ground by means of a strap which exerts a force of 49-N at an angle of 15.7-degrees above the horizontal. What is the normal force exerted by the ground on the suitcase?

311.120

A 41-kg suitcase is being pulled along the ground by means of a strap which exerts a force of 85-N at an angle of 30-degrees above the horizontal. What is the normal force exerted by the ground on the suitcase?

359.3

Squids propel themselves by expelling water from a contractile mantle (jet propulsion). If a squid wished to accelerate up and to the right, in which direction should it eject water?

Down and to the left

Two cars go around a banked curve at the proper speed for the banking angle. One car has tires with excellent traction, while the other car has bald slippery tires. Which of these cars is more likely to slide on the pavement as it goes around the curve?

Neither car will slide

An object is hanging by a string from the ceiling of an elevator. The elevator is slowing down while moving upward. What is the magnitude of the tension in the string? Received only 1 out of 2 points

The magnitude of the tension in the string is less that the magnitude of the weight of the object -

If a projectile is moving through vacuum near the surface of a planet (free fall), which of the following statements must be true?

The only force acting on the object is gravity -the acceleration of the object is constant

In order to simulate weightlessness for astronauts in training, they are flown in a vertical circle. If the passengers are to experience weightlessness, how fast should an airplane be moving at the top of a vertical circle with a radius of 2.5 km?

approx. 160 m/s r x g = v^2

A 15.6-kg load is pulled straight up by a massless rope from the ground to the roof of a building, at a constant acceleration of 0.77 m/s2 . During the upward motion, the tension in the rope is...?

approx. 165 N Fa + Fg =T

You drive your dad's car too fast around a curve and the car starts to skid. What is the correct description of this situation?

friction between tires and road is not strong enough to keep car in circe

If a satellite moves with constant speed in a perfectly circular orbit around the earth, what is the direction of the acceleration of the satellite?

inward toward the earth

You are making a circular turn in your car on a horizontal road when you hit a big patch of ice, causing the force of friction between the tires and the road to become zero. While the car is on the ice, it

moves along a straight path in its original direction

A car goes around a circular curve on a horizontal road at constant speed. What is the direction of the friction force on the car due to the road?

perpendicular to the curve inward

The reason an astronaut in an earth satellite feels weightless is that

the astronaut is falling

An object is at rest on a tabletop. Earth pulls downward on this object with a force equal in magnitude to mg. If this force serves as the action force, what is the reaction force in the action-reaction pair?

the object pulling upward on Earth

You are a passenger in a car, not wearing a seat belt. The car makes a sharp left turn. From your perspective in the car, what do you feel is happening to you?

you are thrown to the right