Physics Test 5
A girl whose weight is 200 N hangs from a bar supported by two vertical strands of rope. What is the tension in each strand?
100 N
A tow truck exerts a force of 300 N on a car, accelerating it at 2 m/s/s. What is the mass of the car?
1500 kg (F=ma)
A 747 jumbo jet has a mass of 30,000 kg. The thrust for EACH OF FOUR engines is 15,000 N. What is the jet's acceleration when taking off?
2 m/s² (F=ma. But your F is multiplied by 4)
A car has a mass of 1000 kg and accelerates at 2 meters per second per second. What is the magnitude of the force acting on the car?
2000 N (F=ma)
When an object reaches terminal velocity its acceleration is
0 m/s²
An apple weighs 1N. The net force on the apple when it is in free fall is
1 N
Suppose the force of friction on a sliding object is 10 N. The force needed to maintain a constant velocity is
10 N
If you pull horizontally on a crate with a force of 150 N and the crate doesn't move, the friction force must be 150 N. Now if you pull with 250 N so the crate slides at constant velocity, the friction force is
250 N
A girl pulls on a 10-kg wagon with a constant force of 30 N. What's the wagon's acceleration?
3.0 m/s² (F=ma)
A jumbo jet cruises at a constant velocity when the total thrust of the engines on the jet is 40,000 N. How much air resistance acts on the jet?
40,000 N
You pull horizontally on a 50 kg crate with a force of 500 N and the friction force on the crate is 250 N. The acceleration of the crate is
5 m/s²
A 10 N falling object encounters 4 N of air resistance. The magnitude of the net force on the object is
6 N
A block is at rest on an incline. The force of friction necessary to prevent the block from sliding increases when the incline angle is
increased
How does acceleration of an object change in relation to its mass? It is
inversely proportional
The reason a tennis ball and a solid steel ball will accelerate at the same rate, in the absence of air resistance, is that
the ball with the larger force also has the larger mass
A tennis ball and a solid steel ball the same size are dropped at the same time. Which ball has the greater force acting on it?
the steel ball
A push on a 1-kilogram brick accelerates the brick. Neglecting friction, to equally accelerate a 10-kilogram brick, one would have to push
with 10 times as much force
Suppose a particle is accelerated through space by a constant 10-N force. Suddenly the particle encounters a second force of 10-N in a direction opposite to that of the first force. The particle
continues at the speed it had when it encountered the second force
Pressure is defined as
force per area
Accelerations are produced by
forces
An apple weighs 1 N. When held at rest above your head, the net force on the apple is
0 N
Which of the following would exert the most pressure on the ground
A woman standing in high heel shoes
A tennis ball and a solid steel ball the same size are dropped at the same time. In the absence of air resistance, which ball has the greater acceleration?
Nonsense! They both have the same acceleration.
As bob falls from a high-flying stationary helicopter, his velocity increases and his acceleration (consider air resistance)
decreases
When the angle of an incline with a block resting on it increases, the normal support force
decreases
