Download Practice Problems 1. A water skier has a mass of 79 kg and

Practice Problems
1. A water skier has a mass of 79 kg and accelerates at 1.4 m/s2. What is the net force
acting on him?
m=79 kg
a=1.4 m/s2 Fnet?
F=ma
F=79x1.4 = 110.6N
2. What is the mass of an object if it takes a net force of 32 N to accelerate it at a rate of
0.88 m/s2?
F=32 N
⁄
⁄
a=0.88 m/s2
m?
3. A net force of 15N is applied to a cart with a mass of 2.1 kg.
a. What is the acceleration of the cart?
⁄
⁄
⁄
b. How long will it take the cart to travel 2.8m, starting from rest?
Using accelleration above, apply kinematic equation K2:
√
4. What is the acceleration of a box weighing 665 N, sitting on a frictionless counter, if a
force of 777 N is horizontally applied to it? (Only the horizontal force causes the
acceleration)
First we can calculate the mass of the box because we know that, W=mg.
We can then apply N2 to solve for acceleration.
5. A car has a mass of 820 kg. It starts from rest and travels 41 m in 3.0 s. What is the net
force applied to the car?
First solve for accleration using K2
Then apply N2, F=ma
6. What will be the final velocity of a 0.005 kg bullet starting from rest, if a net force of 45
N is applied over a distance of 0.80 m?
Use N2 to solve for acceleration: F=ma
Then apply K3 to solve for final velocity.
√
7. A box with a weight of 22N is pulled across a frictionless surface by a rope 43° from the
horizontal surface.
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8. Find the magnitude and direction of the equilibrant force for these two concurrent forces;
13.5 N, east and 32.0 N, north?
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9. A person pulls a rake with 152 N of force along the handle. The angle between the
handle and the ground is 35.0º. Determine the magnitudes of the horizontal and vertical
components of this force.
152 N
X
152Nxcos35°=124.5N
Y
152Nsin35°=87.2N
10. A child pulls a wagon along level ground. The handle which she pulls the wagon makes
an angle of 20.0º with the ground as the child pulls with a force of 78.0 N. What are the
components of this force?
78 N
X
78Nxcos20°=73.3N
Y
78Nsin20°=26.7N
11. What is the mass and weight of a 75kg astronaught on the moon (gmoon= 1.6 m/s2)
Mass ____75kg______
Weight: _____120N______