Questions: A projectile is fired up and to the right at an angle θ(θ ≠ 0° θ ≠ 90°). Identify the directions of the forces listed below that are acting on the projectile when it is at the peak. Gravity ( FG ): -Select- Air drag (Fd) : -Select- Normal force ( FN ): -Select- Kinetic friction (Fk) : -Select- Static friction (Fs) : - Select- Tension (FT) : -Select- Spring force ( Fsp ): -Select-

Solution Steps

We need to identify the directions of the forces acting on a projectile at its peak. The forces listed are:

1. Gravity ($F_{\mathrm{G}}$)
2. Air drag ($F_{d}$)
3. Normal force ($F_{\mathrm{N}}$)
4. Kinetic friction ($F_{\mathrm{k}}$)
5. Static friction ($F_{\mathrm{s}}$)
6. Tension ($F_{T}$)
7. Spring force ($F_{\text{sp}}$)

1. Gravity ($F_{\mathrm{G}}$): Gravity always acts downward towards the center of the Earth.
2. Air drag ($F_{d}$): Air drag opposes the direction of motion. At the peak, the projectile has horizontal velocity, so air drag acts horizontally opposite to the direction of motion.
3. Normal force ($F_{\mathrm{N}}$): Normal force acts perpendicular to the surface of contact. Since the projectile is in the air, there is no contact surface, so the normal force is zero.
4. Kinetic friction ($F_{\mathrm{k}}$): Kinetic friction acts parallel to the surface of contact and opposes relative motion. Since the projectile is in the air, there is no contact surface, so kinetic friction is zero.
5. Static friction ($F_{\mathrm{s}}$): Static friction prevents relative motion between surfaces in contact. Since the projectile is in the air, there is no contact surface, so static friction is zero.
6. Tension ($F_{T}$): Tension is a force exerted by a string, rope, or similar object. Since the projectile is not attached to any such object, tension is zero.
7. Spring force ($F_{\text{sp}}$): Spring force is exerted by a compressed or stretched spring. Since the projectile is not attached to a spring, spring force is zero.

Final Answer